Mo. Rev. Stat. § 354.335

In any action against any corporation subject to the provisions of sections 354.010 to 354.380 to recover the amount of any loss under a policy of health insurance, if it appears from the evidence that such corporation has refused to pay such loss without reasonable cause or excuse, the court or jury may, in addition to the amount thereof and interest, allow the plaintiff damages not to exceed twenty percent of the first fifteen hundred dollars of the loss, and ten percent of the amount of the loss in excess of fifteen hundred dollars and a reasonable attorney's fee; and the court shall enter judgment for the aggregate sum found in the verdict.