Anti-doping (AD) education for athletes is mainly one-way and through passively attended lectures. As such, learning about prohibited substances and highly technical doping rules is often difficult for athletes. Therefore, having athletes passively attending lectures is not enough to prevent unintentional doping violations caused by medicines and supplements. Therefore, it is important for athletes to acquire knowledge about individual prohibited substances as well as active learning and practical knowledge about AD measures. “Doping Guardian” is an educational card game that has been developed to help prevent unintentional doping violations. Participants (pharmacists) of this game can learn how to use medicines and supplements from an AD perspective while simulating the life of an athlete. This presentation will provide an overview of this card game and how it has been used to date.