The first stage of testing new pharmaceuticals in humans is referred to as Phase I clinical trials. The majority of these studies are conducted under controlled, in--‐patient conditions using healthy volunteers who are paid for their participation. This talk draws on an ethnographic study of Phase I clinics to explore the ways in which participants talk about and understand the risks of these clinical trials. It focuses on two sources of information about clinical trials: (1) the information from the formal informed consent process and (2) the information that is shared through social networks of healthy volunteers, especially stories that amount to urban legends about trial participation.