A traditional focus of exercise scientists studying the interaction of drugs and exercise has been on the effects of drugs on exercise performance or functional capacity. In contrast, there is limited information available about the effects of exercise on the efficacy of drugs that have been prescribed and ingested for therapeutic reasons. Those requesting the approval for the manufacture, distribution, and sale of new drugs to the public are required to submit evidence of drug effectiveness and safety to drug regulatory bodies. But, there is no associated requirement to include among that evidence the interactions of exercise with drugs. However, the physiological adaptations to acute and chronic exercise are such that there is good reason to suspect that exercise has the potential to significantly influence drug absorption and bioavailability, drug distribution within the body, and drug elimination from the body. This paper reviews the potential for interaction between exercise and pharmacokinetics.