¶1OPINION
¶2In this medical malpractice case we consider: 1) whether the trial court should have submitted to the jury a requested issue concerning the plaintiff’s contributory negligence; and 2) whether Mary Carter agreements are void as contrary to public policy. The trial court rendered judgment in favor of the plaintiff, and the court of appeals affirmed. 845 S.W.2d 282. We hold that the trial court committed reversible error in refusing to submit an issue on the plaintiff’s contributory negligence. We further hold that Mary Carter agreements are void as against public policy.
¶3I.
¶4At 2:00 a.m. on May 8, 1985, Carole Smith was seriously injured in a single-vehicle accident when the Corvette she was driving left the highway and collided with a tree. She received emergency treatment at the Dallas/Fort Worth Medical Center-Grand Prairie (“D/FW Medical Center”) *242from Dr. Abraham Syrquin for multiple injuries including a compound fracture of her left ankle. In an effort to stop the bleeding, Dr. Syrquin performed emergency surgery closing the ankle wound. Ms. Smith remained under Dr. Syrquin’s treatment for eight days at D/FW Medical Center after which time she was transferred to the care of Dr. James Elbaor, an orthopedic surgeon, at Arlington Community Hospital (“ACH”).
¶5While Ms. Smith was at ACH, she was treated by a team of physicians including Dr. Elbaor, Dr. Joseph Stephens, a plastic surgeon, and Dr. Bienvenido Gatmaitan, an infectious disease specialist. Upon admission to ACH, Ms. Smith was evaluated by Dr. Gatmaitan and placed on intravenous antibiotics. During the course of her stay, Dr. Stephens performed two debridements of the ankle wound.
¶6Ms. Smith’s medical records from D/FW Medical Center and ACH indicate that she refused to cooperate with the instructions of her doctors and nurses. She frequently refused to take her antibiotics, and directed family members to remove weights from her femoral traction device. Some time later, Ms. Smith was transferred to another hospital for surgery to shorten and fuse the bone, leaving her permanently disabled.
¶7Ms. Smith filed suit against D/FW Medical Center, ACH, Drs. Syrquin, Elbaor, Stephens, and Gatmaitan. Sometime before trial, Ms. Smith entered into Mary Carter agreements with Dr. Syrquin, Dr. Stephens, and ACH.
¶8Ms. Smith nonsuited her claim against Dr. Gatmaitan and settled and dismissed her claim against D/FW Medical Center. Dr. Elbaor filed a cross claim against Dr. Stephens, Dr. Gatmaitan,
¶9At trial, the jury found that Ms. Smith’s damages totalled $2,253,237.07, of which Dr. Elbaor was responsible for eighty-eight percent, and Dr. Syrquin for twelve percent. After deducting all credits for Dr. Syrquin’s percentage of causation and settlements with other defendants, the trial *243court rendered judgment against Dr. Elb-aor for $1,872,848.62.
¶10II.
¶11We first consider Dr. Elbaor’s assertion that the trial court erred by refusing to submit to the jury a question on Ms. Smith’s contributory negligence (along with questions addressing his own negligence and that of Drs. Syrquin and Stephens). The court of appeals held that the trial court’s refusal was not error because there was no evidence of Ms. Smith’s contributory negligence. 845 S.W.2d at 284. The court concluded that evidence of Ms. Smith’s refusal of antibiotics only entitled Dr. Elbaor to an instruction on Ms. Smith’s failure to mitigate damages.
¶12Rule 278 of the Texas Rules of Civil Procedure provides that:
[t]he court shall submit the questions, instructions and definitions in the form provided by Rule 277, which are raised by the written pleadings and evidence.
¶13This rule provides a substantive, non-discretionary directive to trial courts requiring them to submit requested questions to the jury if the pleadings and any evidence support them. To determine whether legally sufficient evidence supported Dr. Elb-aor’s contributory negligence submission, we must examine the record for evidence supporting Dr. Elbaor’s question and ignore all evidence to the contrary. See, e.g., Roy v. Howard-Glendale Funeral Home, 820 S.W.2d 844, 846 (Tex.App.—Houston [1st Dist.] 1991, writ denied) (“trial court is obligated to submit the question if the evidence [supporting question] amounts to more than a scintilla”); Times Herald Printing v. A.H. Belo Corp., 820 S.W.2d 206, 215 (Tex.App.—Houston [14th Dist.] 1991, no writ) (in reviewing evidence regarding refused question, appellate court “consider[ed] evidence most favorably in behalf of the complaining party”); Kerrville HRH, Inc. v. City of Kerrville, 803 S.W.2d 377, 383 (Tex.App.—San Antonio 1990, writ denied) (trial court “may refuse to submit a question only if no evidence exists to warrant its submission”); Bryan v. Dockery, 788 S.W.2d 447, 451 (Tex.App.—Houston [1st Dist.] 1990, no writ) (“evidence must be considered in favor of the party against whom the questions were refused and if it supports the question then it must be submitted”); Phillips Pipeline Co. v. Richardson, 680 S.W.2d 43, 48 (Tex.App.—El Paso 1984, no writ) (“evidence must be considered most favorably in behalf of the party against whom the issues were refused, and if there is any conflicting probative evidence in the record, those questions are for the jury’s determination”). A trial court may refuse to submit an issue only if no evidence exists to warrant its submission. Brown v. Goldstein, 685 S.W.2d 640, 641 (Tex.1985) (where evidence was conflicting, it is error to refuse submission of contributory negligence issues); Garza v. Alviar, 395 S.W.2d 821, 824 (Tex.1965) (contention that question should not have gone to jury only sustainable if no evidence supports question).
¶14In order to determine whether Dr. Elb-aor’s questions should have been presented to the jury, we must examine the record to see if there is some evidence that Ms. Smith’s refusal to take antibiotics arguably preceded the onset of infection in her ankle. If we find some evidence indicating that Ms. Smith may have been contribu-torily negligent, then we must conclude that the trial court should have submitted Dr. Elbaor’s requested contributory negligence question; and accordingly, we must reverse this cause and remand it for a new trial.
¶15A brief chronology of events will aid our analysis. After the accident on May 8, 1985, Ms. Smith was treated by Dr. Syr-quin at D/FW Medical Center for injuries to her left shoulder, femur, and ankle. On May 17, she was transferred to ACH and into the care of Drs. Elbaor, Stephens, and Gatmaitan. She remained under their care until she was transferred to Baylor on June 3.
¶16Shortly after Ms. Smith arrived at ACH, Dr. Gatmaitan rendered an initial diagnosis concluding that her ankle was infected, and *244he began treating her with intravenous antibiotics.
¶17The foregoing discussion reveals that the record contained some evidence that Ms. Smith’s ankle was not infected when she arrived at ACH on May 17, 1985. Further, the record indisputably indicates that Ms. Smith refused antibiotics, essential to the maintenance of her ankle’s health, throughout her stay at ACH. Taken together, this evidence amounts at least to some evidence supporting Dr. Elbaor’s assertion of Ms. Smith’s contributory negligence. Accordingly, the trial court should have submitted it to the jury. See Southwestern Bell Tel. Co. v. Thomas, 554 S.W.2d 672, 674 (Tex.1977) (trial court must submit issues if there is “some evidence” of contributory negligence).
¶18Dr. Elbaor properly preserved error regarding the trial court’s wrongful refusal of the contributory negligence questions, instructions, and definitions. He complained during the charge conference that the court’s submission failed to adequately account for Ms. Smith’s contributory negligence. He also submitted contributory negligence and proximate cause questions in “substantially correct wording” as required by Rule 278. See Placencio v. Allied Indus. Int’l Exch., 724 S.W.2d 20, 21 (Tex.1987).
¶19The court of appeals held that the evidence raised issues of failure to miti*245gate, but not contributory negligence. As we have observed, “[njegligence that merely increases or adds to the extent of the loss or injury occasioned by another’s negligence is not ... contributory negligence.” Kerby v. Abilene Christian College, 503 S.W.2d 526, 528 (Tex.1973). In Kerby, the plaintiff was driving a delivery truck with its sliding door open. He collided with a bus, the force of which threw him from the truck, causing him serious injuries. The trial court submitted a question on the driver’s contributory negligence. Id. at 527. This Court held that the trial court should have accounted for any increase in injury caused by the plaintiff driving with the door open through a mitigation of damages question, and not one of contributory negligence. For this reason, the dissent’s reliance on Kerbyis misplaced.
¶20Moreover, the instant case is fundamentally distinguishable from Kerby. Driving a delivery truck with its sliding door open is neither an intrinsically harmful act, nor is it a breach of a legal duty. However, the unusual act of refusing to take antibiotics, which a medical doctor has prescribed to preserve a patient’s health, plainly may cause harm. Additionally, it breaches a duty of cooperation which patients owe treating physicians who assume the duty to care for them. Ms. Smith was arguably free of infection when she arrived at ACH. She began breaching her duty to cooperate from the moment she arrived by refusing antibiotics, and she remained uncooperative throughout her stay at ACH. Ms. Smith’s refusal to take the antibiotics also constituted an inherently harmful act, because, as the testimony at trial demonstrated, refusing antibiotics can permit an infection to develop. Thus, her refusal of medication essential to maintaining her health created a fact issue as to whether she contributed to the infection that eventually afflicted her ankle.
¶21Furthermore, the Court in Kerbyheld that the plaintiff’s conduct of driving with the door open was not contributory negligence because it did not contribute to the accident; rather, it only increased the injuries suffered in the accident. In the present case, the “accident” equates to the medical problem complained of: Ms. Smith’s infected ankle. Her conduct arguably did contribute to the infection. In Kerby, there would have been a wreck, and a lawsuit, even if the plaintiff had kept the door of his truck closed. Here, there might have been no infection, and thus no claim of medical malpractice, had Ms. Smith followed her doctors’ instructions.
¶22The trial court improperly addressed Ms. Smith’s conduct through a mitigation of damages instruction. The plain language of Rule 278 bound the trial court to submit Dr. Elbaor’s question. Dr. Elbaor pleaded that Ms. Smith committed contributory negligence by refusing to take antibiotics while under his care at ACH, and he put on evidence at trial supporting his assertion that Ms. Smith’s refusal to take antibiotics contributed to her injury. Therefore, the trial court in this case failed to follow the directive of Rule 278. Instead, the trial court chose to account for Ms. Smith’s negligence by submitting an instruction on mitigation of damages which instructed the jury to exclude from its verdict any damages attributable to Ms. Smith’s negligence. This instruction contained no definition of negligence upon which the jury could have based its decision as to whether she was negligent. See Griffin v. Eakin, 656 S.W.2d 187, 190 (Tex.App.—Austin 1983, writ ref’d n.r.e.) (absence of negligence definition confuses jury burdened with resolving negligence question).
¶23III.
¶24As previously noted, Ms. Smith entered into Mary Carter agreements with Dr. Syr-*246quin,
¶25Dr. Syrquin had performed emergency surgery on Ms. Smith’s ankle. Testimony at trial revealed that Dr. Syrquin, who was not an orthopedic specialist, committed malpractice by closing the ankle too soon after debriding it. Eight days after the surgery, Dr. Syrquin recommended transferring Ms. Smith to ACH where she came under the care of, among others, Dr. Elbaor, an orthopedic specialist. At ACH, Dr. Elbaor observed but did not participate in two additional debridements of Ms. Smith’s ankle which were performed by Dr. Stephens, a plastic surgeon. Dr. Stephens sought to explore and alleviate any infection in Ms. Smith’s ankle. Additional expert medical testimony elicited during the trial demonstrated that, in all probability, Ms. Smith’s ankle was beyond restoration by the time she arrived at ACH. Arguably neither the subsequent surgeries performed at ACH nor the care she received there could have remedied the damage caused by Dr. Syr-quin’s malpractice.
¶26Although the Mary Carter agreements were not entered into evidence, the trial judge was troubled by them and he took remedial measures to mitigate their harmful effects by reapportioning the peremptory challenges, changing the order of proceedings to favor Dr. Elbaor, allowing counsel to explain the agreements to the jury, and instructing the jury regarding the agreements.
¶27During the trial, the settling defendants’ attorneys, who sat at the table with Dr. Elbaor’s attorneys, vigorously assisted Ms. Smith in pointing the finger of culpability at Dr. Elbaor. This created some odd conflicts of interest and some questionable representations of fact. For example, although Ms. Smith’s own experts testified that Dr. Syrquin committed malpractice, her attorney stated during voir dire and in her opening statement that Dr. Syrquin’s conduct was “heroic” and that Dr. Elbaor’s negligence caused Ms. Smith’s damages. And during her closing argument, Ms. Smith’s attorney urged the jury to find that Dr. Syrquin had not caused Ms. Smith’s damages. This is hardly the kind of statement expected from a plaintiff’s lawyer regarding a named defendant. ACH and Drs. Syrquin and Stephens had remained defendants of record, but their attorneys asserted during voir dire that Ms. Smith’s damages were “devastating," “astoundingly high,” and “astronomical.” Furthermore, on cross examination they elicited testimony from Ms. Smith favorable to her and requested recovery for pain and mental anguish. The settling defendants’ attorneys also abandoned their pleadings on Ms. Smith’s contributory negligence, argued that Ms. Smith should be awarded all of *247her alleged damages, and urged that Dr. Elbaor was 100 percent liable.
¶28A.
¶29The term “Mary Carter agreement” has been defined in different ways by various courts and commentators.
¶30A Mary Carter agreement exists, under our definition, when the plaintiff enters into a settlement agreement with one defendant and goes to trial against the remaining defendants). The settling defendant, who remains a party, guarantees the plaintiff a minimum payment, which may be offset in whole or in part by an excess judgment recovered at trial. See General Motors Corp. v. Simmons, 558 S.W.2d 855, 858 (Tex.1977), overruled on other grounds by Duncan v. Cessna Aircraft Co., 665 S.W.2d 414, 427 (Tex.1984). This creates a tremendous incentive for the settling defendant to ensure that the plaintiff succeeds in obtaining a sizable recovery, and thus motivates the defendant to assist greatly in the plaintiffs presentation of the case (as occurred here). Indeed, Mary Carter agreements generally, but not always, contain a clause requiring the set*248tling defendant to participate in the trial on the plaintiff’s behalf.
¶31Given this Mary Carter scenario, it is difficult to surmise how these agreements promote settlement. Although the agreements do secure the partial settlement of a lawsuit, they nevertheless nearly always ensure a trial against the non-settling defendant. Bedford School Dist. v. Caron Constr. Co., 116 N.H. 800, 867 A.2d 1051, 1054 (1976) (agreement required plaintiff to prosecute claim against remaining defendant and plaintiff could not settle the claim for under $20,000 without the consent of the settling defendant); Lum v. Stinnett, 87 Nev. 402, 488 P.2d 347, 348 (1971) (same). Mary Carter agreements frequently make litigation inevitable, because they grant the settling defendant veto power over any proposed settlement between the plaintiff and any remaining defendant. See Bass v. Phoenix Seadrill/78 Ltd., 749 F.2d 1154, 1156 (5th Cir.1985) (Mary Carter agreement gave settling defendant veto power). Thus, “[o]nly a mechanical jurisprudence could characterize Mary Carter arrangements as promoting compromise and discouraging litigation — they plainly do just the opposite.” Stein v. American Residential Mgmt., 781 S.W.2d 385, 389 (Tex.App.—Houston [14th Dist.] 1989), writ denied per curiam, 793 S.W.2d 1 (Tex.1990).
¶32In his concurring opinion in Scurlock Oil Co. v. Smithwick, 724 S.W.2d 1, 8 (Tex.1986) (on motion for rehearing), Justice Spears pointed out that “Mary Carter agreements should be prohibited because they are inimical to the adversary system, and they do not promote settlement — their primary justification.” The truth of this statement has been recognized by commentators and has been proven by the subsequent history regarding the use of Mary Carter agreements.
¶33The dissent approves of the supervisory guidelines suggested in the Smithwickconcurrence, but his opinion misses the point. These guidelines were suggested as a stopgap measure to ameliorate the harmful effects of Mary Carter agreements until this Court finally ruled on the agreements’ propriety. Our inaction has created confusion, because the question as to whether Mary Carter agreements are valid has remained open. See, e.g., Stein, 781 S.W.2d at 388 (“Texas Supreme Court has not passed squarely on the question of [Mary Carter agreements’] validity”); Adams v. Petrade Int’l, Inc., 754 S.W.2d 696, 718 (Tex.App.—Houston [1st Dist.] 1988, writ denied) (“the Texas Supreme Court has not held that such settlements are invalid”); Lubbock Mfg. Co. v. Perez, 591 S.W.2d 907, 920 (Tex.Civ.App.—Waco 1979, dism. agr.) (whether Mary Carter agreements are against public policy is “matter for determination by our Supreme Court of Texas”).
¶34B.
¶35Many jurisdictions have decided to tolerate the ill effects of Mary Carter agreements, presumably because they believe that the agreements promote settlement. Some have sought to mitigate the agreements’ harmful skewing of the trial process by imposing prophylactic protections.
¶36Justice Spears rightly noted in Smithwickthe falsity of the premise upon which the prophylactic protection approach is founded, namely, the promotion of equitable settlements. Id. at 8. Mary Carter agreements instead:
present to the jury a sham of adversity between the plaintiff and one co-defendant, while these parties are actually allied for the purpose of securing a substantial judgment for the plaintiff and, in some cases, exoneration for the settling defendant.
¶37June F. Entman, Mary Carter Agreements: An Assessment of Attempted Solutions, 38 U.Fla.L.Rev. 521, 574 (1986); see also General Motors Corp. v. Lahocki, 286 Md. 714, 410 A.2d 1039, 1046 (1980). The agreements pressure the “settling” defendant to alter the character of the suit by contributing discovery material, peremptory challenges, trial tactics, supportive witness examination, and jury influence to the plaintiffs cause. See John E. Benedict, Note, It’s A Mistake to Tolerate the Mary Carter Agreement, 87 Columbia L.Rev. 368, 372-73 (1987). These procedural advantages distort the case presented before a jury that came “to court expecting to see a contest between the plaintiff and the defendants [and] instead see[s] one of the defendants cooperating with the plaintiff.” Smithwick, 724 S.W.2d at 9 (Spears, J., concurring).
¶38Mary Carter agreements not only allow plaintiffs to buy support for their case,
¶39IV.
¶40The case before us reveals yet another jury trial and verdict distorted by a Mary Carter agreement. The trial judge, who fully grasped the detrimental effect these agreements could have on the outcome, attempted to monitor the lawsuit by assiduously applying the guidelines suggested in the Smithwickconcurrence. The conduct of this trial, however, confirms the apprehension expressed by Justice Spears in Smithwick: that these remedial measures would only mitigate and not eliminate the unjust influences exerted on a trial by *250Mary Carter agreements. Equalizing peremptory strikes, reordering proceedings, thoroughly disclosing the true alignment of the parties, and revealing the agreement’s substance cannot overcome collusion between the plaintiff and settling defendants who retain a financial interest in the plaintiffs success. In fact, Mary Carter agreements may force attorneys into questionable ethical situations under Rule 3.05 of the Texas Disciplinary Rules of Professional Conduct, which is titled “Maintaining the Impartiality of the Tribunal.” Comment 2 to that rule notes, regarding alternate methods of dispute resolution (like Mary Carter agreements), that “a lawyer should avoid any conduct that is or could reasonably be construed as being intended to corrupt or to unfairly influence the decision-maker.” See SUPREME Court of Texas, Texas Disciplinary Rules of Professional Conduct art. X, § 9 (1990); cf. Model Code of Professional Responsibility EC-720 (1979) (attorneys responsible for upholding adversarial system). The dissent acknowledges that Mary Carter agreements skew the trial process. This effect reasonably could be construed as unfairly influencing the deci-sionmaker.
¶41As a matter of public policy, this Court favors settlements, but we do not favor partial settlements that promote rather than discourage further litigation. And we do not favor settlement arrangements that skew the trial process, mislead the jury, promote unethical collusion among nominal adversaries, and create the likelihood that a less culpable defendant will be hit with the full judgment. The bottom line is that our public policy favoring fair trials outweighs our public policy favoring partial settlements.
¶42This case typifies the kind of procedural and substantive damage Mary Carter agreements can inflict upon our adversarial system. Thus, we declare them void as violative of sound public policy.
¶43However, we do recognize the hardships that our decision today will create on our already burdened courts. Thus, we must decide whether our decision voiding Mary Carter agreements will apply prospectively or retrospectively. Although our decisions usually apply retrospectively, exceptions are recognized when considerations of fairness and policy dictate prospective effect only. Duncan v. Cessna Aircraft Co., 665 S.W.2d 414, 434 (Tex.1984). In Carrollton Farmers Branch Ind. School Dist. v. Edgewood Ind. School Dist., 826 S.W.2d 489, 518-19 (Tex.1992), we adopted the three factors from the United States Supreme Court’s decision in Chevron Oil Co. v. Huson, 404 U.S. 97, 106-07, 92 S.Ct. 349, 355-56, 30 L.Ed.2d 296 (1971) to determine whether to apply a decision prospectively or retroactively. These factors are: (1) whether the decision establishes a new principle of law by either overruling clear past precedent on which litigants may have relied or by deciding an issue of first impression whose resolution was not clearly foreshadowed; (2) whether prospective or retroactive application of the particular rule will further or retard its operation through an examination of the history, purpose, and effect of the rule; and (3) whether retroactive application of the rule could produce substantial inequitable results. Id.
¶44The first and the third of these factors weigh clearly in favor of a determination of prospective application. This case represents an issue of first impression whose resolution was not clearly foreshadowed. Although commentators have routinely criticized the Mary Carter agreement, only a couple of states have previously held that such agreements are void.
¶45V.
¶46In short, the evidence in the record creates a fact issue of comparative causation. The jury should have been allowed to pass not only on Drs. Elbaor’s, Syrquin’s, and Stephens’ alleged negligence, but also on Ms. Smith’s alleged negligence. Under this record, the trial court should have left these fact issues for the jury’s resolution within the framework of our well-established comparative negligence law. The failure to submit the issues was calculated to cause, and probably did cause, the rendition of an improper judgment in this case. Tex.R.App.P. 81. The danger in allowing the trial court’s action to stand uncorrected is that this would indicate that patients who refuse to take medication necessary to their recovery are not contributorily negligent even though their unwillingness may have causally contributed to their injuries. Additionally, the judgment in this case was fundamentally driven by Mary Carter agreements. However, because of the existence of a severability clause in some of the agreements but not others and the creation of a financial stake for some defendants in Ms. Smith’s lawsuit but not in others, they must be treated separately.
¶47Agreement between Ms. Smith and Arlington Community Hospital: Because of the severability clause, the portion of the agreement between Ms. Smith and ACH creating ACH’s financial stake in the outcome of the case and requiring ACH to participate in the trial is severed from the rest of the agreement and held null and void.
¶48Agreement between Ms. Smith and Dr. Syrquin: This agreement did not contain a severability clause but Dr. Syr-quin retained a financial state in Ms. Smith’s lawsuit and was required to participate in the trial. The portion of the agreement granting Dr. Syrquin a financial stake in Ms. Smith’s lawsuit is nonetheless held null and void. So as not to interfere with the parties’ right to contract, we leave it to the parties, if they so choose, to develop before the trial court whether this void provision is severable, or whether the entire agreement must fail.
¶49Agreement between Ms. Smith and Dr. Stephens: This agreement did not create a financial stake for Dr. Stephens in *252Ms. Smith’s lawsuit. Thus, this agreement does not meet the test for a Mary Carter agreement.
¶50In summary, a settling defendant may not participate in a trial in which he or she retains a financial interest in plaintiff’s lawsuit. Since Dr. Stephens does not have a financial interest in Ms. Smith’s lawsuit, there is no impediment for him to participate fully in the re-trial of this case as any other party. ACH possesses a financial interest in Ms. Smith’s lawsuit, but it can also participate in the re-trial of the case because we have severed the portion of the agreement creating ACH’s financial stake in the outcome of the case from the remainder of the settlement. Likewise, Dr. Syr-quin does have a financial interest in Ms. Smith’s lawsuit and was required to participate in the trial. We have held the portion of the agreement granting Dr. Syrquin a financial interest in Ms. Smith’s cause of action against Dr. Elbaor null and void. However, his future participation in the retrial of this case has yet to be determined. After a hearing, if the trial court invalidates the entire agreement for lack of consideration or for some other reason, Ms. Smith is obligated to return the settlement funds to Dr. Syrquin and he is free to participate in the re-trial of this cause as any other party. Accordingly, we reverse the judgment of the court of appeals and remand this cause to the trial court for further proceedings consistent with this opinion.
¶51. See section III A of this opinion, infra.
¶52. "Debridement” is the removal of foreign material and contaminated or devitalized tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Dorland’s Pocket Medical Dictionary 187 (23rd ed. 1982).
¶53. These agreements acquired their name from a case out of Florida styled Booth v. Mary Carter Paint Co., 202 So.2d 8, 10-11 (Fla.App.1967). When the Florida Supreme Court finally addressed Mary Carter agreements, it noted their potential to skew the trial process and thus established supervisory guidelines to limit their ill effects. See Ward v. Ochoa, 284 So.2d 385 (Fla.1973).
¶54.Dr. Gatmaitan was later dismissed from the lawsuit after Dr. Elbaor nonsuited his claim against him.
¶55. Dr. Robert Sorokolit, a medical expert, testified that Dr. Gatmaitan erred in his diagnosis of Ms. Smith's ankle because: (1) Ms. Smith had no fever; (2) Dr. Gatmaitan's notes said "nothing about drainage, nothing about erythema (sic), [and] nothing about odor;" and (3) the May 18 culture taken from ankle showed no bacterial growth. Based on these factors, Dr. Sorokolit concluded that Ms. Smith’s ankle must not have been infected.
¶56. Regarding the consequences of a patient’s refusing antibiotics, Dr. Gaines, an orthopedic surgeon and recognized expert, testified that: Bacteria is capable of reproducing itself in anywhere from 20 minutes to an hour and a half. Antibiotics last much longer than that in the system, and one uses the continuous influx of antibiotics to knock down the numbers of bacteria. If you skip your dose, then those bacteria reduplicate very quickly and outrun the simple proportionate amount of time that you lag on your drug treatment. So skips in dosages are very, very important.
¶57.The record also contains evidence that Ms. Smith refused antibiotics while at D/FW Medical Center, even before she was transferred to ACH.
¶58. The trial court’s submission on mitigation of damages read:
Do not include any amount for any condition resulting from the failure, if any, of Carole Mercer Smith to have acted as a person of ordinary prudence would have under the same or similar circumstances in caring for herself and cooperating in the treatment of her injuries, if any that resulted from the medical care made the basis of the lawsuit.
¶59. This agreement called for Dr. Syrquin to pay Ms. Smith $350,000 contemporaneously with the signing of the agreement. Dr. Syrquin retained a financial stake in Ms. Smith’s lawsuit, and was required to participate in the trial of the case. The agreement did not contain a severability clause.
¶60. This agreement called for ACH to pay Ms. Smith $75,000 contemporaneously with the signing of the agreement. ACH retained a financial stake in Ms. Smith’s lawsuit against the other defendants, and ACH was required to participate in the trial of the case. The agreement also contained a severability clause which provided: “If any part of this Agreement is declared by a Court of competent jurisdiction to be invalid or unenforceable, such portion shall be deemed severed from this Agreement, and the remaining part shall remain in full force and effect as if the invalid or unenforceable provision had not been a part of this Agreement.”
¶61. This agreement provided that Dr. Stephens pay Ms. Smith $10 contemporaneously with the signing of the agreement. It required Dr. Stephens’ participation at trial, but it did not create a financial stake in the trial for Dr. Stephens.
¶62. In response to Dr. Elbaor’s request to void the Mary Carter agreements, the trial judge evinced some doubt regarding their propriety:
Well, you know, if I were a justice on the Supreme Court and this was before me, I might rewrite — try to rewrite the law on [Mary Carter agreements]....
¶63.The majority of cases and commentators define "Mary Carter agreement" as one in which the settling defendant possesses a financial stake in the outcome of the case and the settling defendant remains a party to the litigation. See Ward v. Ochoa, 284 So.2d 385, 387 (Fla.1973); General Motors Corp. v. Lahocki, 286 Md. 714, 410 A.2d 1039, 1042 (1980); Johnson v. Moberg, 334 N.W.2d 411, 415 (Minn.1983); Bedford School Dist. v. Caron Constr. Co., 116 N.H. 800, 367 A.2d 1051, 1053 (1976); Cox v. Kelsey-Hayes Co., 594 P.2d 354, 357 (Okla.1978); General Motors Corp. v. Simmons, 558 S.W.2d 855, 858 (Tex.1977); Vermont Union School Dist. v. H.P. Cummings Constr. Co., 143 Vt. 416, 469 A.2d 742, 748 (1983); John E. Benedict, Note, It's a Mistake to Tolerate the Mary Carter Agreement, 87 Columbia L.Rev. 368, 369-70 (1987); David R. Miller, Comment, Mary Carter Agreements: Unfair and Unnecessary, 32 Sw.L.J. 779, 783-84 (1978). Many cases also describe other requisite elements of a Mary Carter agreement, such as secrecy. See, e.g., Ward, 284 So.2d at 387. Other cases and commentators argue that a Mary Carter agreement exists any time the settling defendant possesses a financial interest in the plaintiff s recovery. See Bristol-Myers Co. v. Gonzales, 561 S.W.2d 801, 805 (Tex.1978); Robin Renee Green, Comment, Mary Carter Agreements: The Unsolved Evidentiary Problems in Texas, 40 Baylor L.Rev. 449, 451 (1988).
¶64. A Mary Carter agreement does not have to expressly state that the settling defendant must participate in the trial. The participation requirement is satisfied by the mere presence of the settling defendant as a party in the case. Obviously, a Mary Carter agreement would not exist if a settling defendant acquires a financial interest in the outcome of the trial and then testifies at trial as a non-party witness. However, Rule 3.04(b) of the Texas Disciplinary Rules of Professional Conduct prohibits a lawyer from paying or offering to pay a witness contingent upon the content of the testimony of the witness or the outcome of the case. Certainly Rule 3.04(b) mandates that an attorney has an ethical duty to refrain from making a settlement contingent, in any way, on the testimony of a witness who was also a settling party.
¶65. See supra note 13.
¶66. The first case to utilize the term "Mary Carter agreement” was Ward v. Ochoa, 284 So.2d 385, 386 (Fla.1973). The Florida Supreme Court defined a Mary Carter agreement as “a contract by which one co-defendant secretly agrees with the plaintiff that, if such defendant will proceed to defend himself in court, his own maximum liability will be diminished proportionately by increasing the liability of the other co-defendants.” Id. at 387.
¶67. Numerous commentators have criticized Mary Carter agreements. See, e.g., June F. Ent-inan, Mary Carter Agreements: An Assessment of Attempted Solutions, 38 U.Fla.L.Rev. 521 (1986); Robin Renee Green, Comment, Mary Carter Agreements: The Unsolved Evidentiary Problems in Texas, 40 Baylor L.Rev. 449 (1988); John E. Benedict, Note, It’s A Mistake to Tolerate the Mary Carter Agreement, 87 Columbia L.Rev. 368 (1987); Richard Casner, Note, Admission into Evidence of a Mary Carter Agreement from a Prior Trial is Harmful Error, 18 Tex.Tech L.R. 997 (1987); David R. Miller, Comment, Mary Carter Agreements: Unfair and Unnecessary, 32 Sw.L.J. 779 (1978).
¶68. See, e.g., Sequoia Mfg. Co. v. Halec Constr. Co., 117 Ariz. 11, 570 P.2d 782 (App.1977); Shelton v. Firestone Tire & Rubber Co., 281 Ark. 100, 662 S.W.2d 473 (1983); Ward v. Ochoa, 284 So.2d 385 (Fla.1973); Palmer v. Avco Distrib. Corp., 82 Ill.2d 211, 45 Ill.Dec. 377, 412 N.E.2d 959 (1980); General Motors Corp. v. Lahocki, 286 Md. 714, 410 A.2d 1039 (1980); Johnson v. Moberg, 334 N.W.2d 411 (Minn.1983); Hegarty v. Campbell Soup Co., 214 Neb. 716, 335 N.W.2d 758 (1983); Bedford School Dist. v. Caron Constr. Co., 116 N.H. 800, 367 A.2d 1051 (1976); Corn Exch. Bank v. Tri-State Livestock Auction Co., 368 N.W.2d 596 (S.D.1985); State ex rel. Vapor Corp. v. Narick, 173 W.Va. 770, 320 S.E.2d 345 (1984).
¶69. The guidelines provided in the Smithwickconcurrence require that Mary Carter agreements: (1) are discoverable: (2) should be fully disclosed "to the trial court before trial or immediately after the agreement is formed;” (3) should be considered by the trial court in allowing jury strikes and ruling on witness examination; and (4) should be fully disclosed to the jury at the start of the trial. Smithwick, 724 S.W.2d at 8-11.
¶70. We previously condemned the practice of buying a witness’ testimony in order to silence testimony. Tom L. Scott, Inc. v. McIlhany, 798 S.W.2d 556, 560 (Tex.1990).
¶71. The agreements are void in Nevada and Wisconsin. Lum v. Stinnett, 87 Nev. 402, 488 P.2d 347 (1971); Trampe v. Wisconsin Tel. Co., 214 Wis. 210, 252 N.W. 675 (1934). Oklahoma reached a similar result by holding that a trial court must "either hold that portion of the agreement granting agreeing defendant an interest in a large plaintiffs verdict unenforceable as against public policy, or dismiss the agreeing defendant from the suit.” Cox v. Kelsey-Hayes Co., 594 P.2d 354, 359 (Okl.1978) (emphasis in original).
¶72. Several federal cases have similarly held that the first and third prongs can mandate pros-pectivity even when the second prong favors retroactivity. See Silverman v. Barry, 845 F.2d 1072, 1085-86 (D.C.Cir.), cert. denied, 488 U.S. 956, 109 S.Ct. 394, 102 L.Ed.2d 383 (1988); Barina v. Gulf Trading & Transp. Co., 726 F.2d 560, 564 (9th Cir.1984); Stretton v. Penrod Drilling Co., 701 F.2d 441, 445-46 (5th Cir.1983).
¶73. The complaining party on appeal is not relieved of the standard appellate requirements of preservation of error and establishing that the error "was reasonably calculated to cause and probably did cause the rendition of an improper judgment.” TexJR.App.P. 81(b) & 184(b); see also Tex.R.App.P. 52. In this case, we determine that the use of the Mary Carter agreement at trial was harmful error for the reasons stated in section III of this opinion.