Prescription medication can often be purchased in Mexico without a physician's prescription. United States residents living along the border may have access to dangerous medications by crossing the border and purchasing them in Mexican pharmacies. We sought to determine the extent and frequency of this behavior in a sample of our ambulatory clinic population. Patients from the Texas Tech University Internal Medicine Clinic were surveyed to collect information about their use of medications, use of alternative sources of health care in Mexico, and purchasing of prescription medication in Juarez, Mexico. More than 80% of patients stated they had purchased prescription-type medication at a pharmacy without a physician's prescription. The most common reasons for buying prescription medication in Mexico were because it was less expensive or because a prescription was not necessary. These data indicate a potential for US residents along the border to take medications in an unregulated manner, a practice that could pose problems for health care providers on both sides of the border.