This article provides a thorough ethico-legal analysis of Article 23b(1) of the Polish Act on the Professions of Physician and Dentist (APPD). The analyzed provision regulates the permissibility of paying participants in medical experiments in the form of reimbursement of incurred expenses as well as in the form of “incentives and financial rewards”. First, we define the scope of Article 23b(1) of the APPD within the context of the legal concept of a medical experiment. Then, we discuss the regulatory gaps and interpretive issues posed by Article 23b(1). We highlight significant discrepancies between the Polish regulations on payment for participation in medical experiments and relevant EU provisions on payment for participation in clinical trials. We also compare Article 23b(1) with the guidelines on research payment endorsed by important international ethical and legal standards for human medical research. Ultimately, we conclude that the analyzed provision of the APPD requires revision to better protect participants of medical experiments, as well as to provide researchers and research ethics committees with clearer, more coherent, and better-justified payment guidance.