The use of addictive substances tends to be viewed by most Americans as an immoral act instead of an acceptable but potentially harmful personal preference. This suggests that guilt, a sociomoral emotion associated with internalized standards and societal mores, can be an important influence on drug-use behavior. In exploring this issue, the current study recruited a sample of 230 undergraduates (105 males and 125 females) from an urban university. Participants were asked to describe three times they had felt guilty, to rate the intensity of their guilt response, to describe how they responded to or coped with the situation, to rate how effective their response was in alleviating their guilt, and to state how long ago each guilt-eliciting event occurred. The scales relevant to the measurement of guilt were administered early in a 2-hour session, and the items related to substance use were presented near the end of the session. Various personality measures not relevant to the findings reported in this article were interspersed between the guilt measures and the substance use indexes. The study found that substance users had lower scores on standards and situational guilt than nonusers, but no difference was observed in chronic guilt. This study thus suggests that a stronger internalization of societal standards, as reflected by higher scores on standards and situational guilt, may prove to be a useful tool in preventing substance use. 5 tables and 66 references