The increasing development of resistant pathogens is one of the greatest global health challenges. As antibiotic overuse amplifies antibiotic resistance, antibiotic intake poses a social dilemma in which individuals need to decide whether to prosocially reduce their intake in the collective interest versus to (over)use it even in case of mild diseases. We devise a novel behavioral game paradigm to model the social dilemma of antibiotic intake. Using this new method in an incentivized laboratory experiment (N = 272 German participants), we varied whether players had mutual knowledge about their antibiotic intake. The results indicate that there was substantial antibiotic overuse in the absence of social information. Overuse decreased when social information was present. Our postexperimental survey data further suggest that social information impacts people's behavioral motivation, evaluation of the other player, and positive affect. Taken together, providing social information about people's antibiotic intake may help in reducing antibiotic overuse. On a more general level, the novel behavioral game may be adapted to study other aspects of antibiotic intake to promote prudent use of antibiotics.