The objectives of this research were to explore lay medication activities as an aspect of self-managed health care in the Canadian context and to identify the sociodemographic and sociomedical characteristics of those who engage in self-medication. Interview data were collected in 1983 from a random cross-sectional sample of 524 adult residents living in Winnipeg, Canada. Respondents were questioned about the types of medicines they keep in their home (both prescribed and nonprescribed), self-treated symptomatic conditions; recent medication activities, the use of prescribed medicine in self-treated illness episodes, and the use of home remedies. This study contributes to a growing body of international evidence that has demonstrated that self-medication is a vital part of daily self-care behavior. For the most part, the results are comparable to those reported by previous British and U.S. studies of self-medication. Winnipeg residents were found to be active self-care providers who engage in a variety of self-medication practices. The study also illustrates the fact that the altered use of prescribed drugs (particularly by those with higher levels of formal education) is an important aspect of self-medication behavior. These findings have clear implications for health care practitioners.