More than 100,000 over-the-counter (OTC) products are now sold in drugstores, convenience stores, gas stations, and supermarkets. In 1997, the OTC retail market was responsible for an estimated $20.6 billion in health care savings. This article discusses the methods by which drugs are approved for OTC use by the Food and Drug Administration. The article also reviews trends and issues related to self-care with OTC medications, including cost-effectiveness, managed care, advertising, and safety. The clinician should assume that OTC use is a common patient self-care behavior; therefore, information regarding the patient's OTC use-should be collected during the history taking. Other implications of OTC use for primary care providers are proposed.