Okla. Stat. tit. 59, § 731.3

Except as authorized by the provisions of Sections 492 and 731.5 of this title and Section 5 of this act, no person shall in any manner engage in, offer to engage in, or hold himself out as qualified to engage in the diagnosis and/or treatment of any human ill unless such person is the holder of a legal and unrevoked license or certificate issued under the laws of Oklahoma authorizing such person to practice the healing art covered by such license and is practicing thereunder in the manner and subject to the limitations provided by the laws of the State of Oklahoma for the issuance of such license or certificate for the practice thereunder.