OBJECTIVES: The purpose of this study was to describe ethnic differences in physician-patient communication about alternative therapies, using a data set comprised of audiotapes and transcripts of primary care medical visits. METHODS: The data set was collected during 1995 at the family practice and general medicine clinics at the University of New Mexico Health Sciences Center, Albuquerque, NM. Twenty-seven (27) resident physicians and 205 of their Hispanic and non-Hispanic white patients age 50 and over participated. RESULTS: Almost 18 percent of patients reported using one or more alternative therapies during the preceding month. Herbal medicine was the most widely used therapy. Eighty-three percent (83%) of patients who reported using an alternative therapy in the previous month did not tell their physicians. Physicians asked one or more questions about alternative therapies during only 3.4% of encounters. Only 2% of patients asked their physicians one or more questions about alternative therapies. There were no ethnic differences in physician-older patient communication about alternative therapies. DISCUSSION: Physician-patient communication could be improved to enhance physician understanding of the spectrum of interventions patients pursue to improve their health.