The Food and Drug Administration received about 37000 adverse drug reaction reports in 1985. Seventy-one percent of the reports involved toxic reactions to usual doses of drugs and were sent by medical care professionals directly to the Food and Drug Administration or to pharmaceutical manufacturers. In terms of severity, 2% of reports involved death while 21% involved hospitalization. The highest proportions of hospitalization or death were found for reports describing cardiovascular, hematologic, or respiratory effects. Nearly half of the reported deaths were in patients more than 59 years of age. The majority of reports described an adverse drug reaction occurring within two weeks of initial exposure to the suspected drug. Adverse drug reaction reporting by physicians is crucial to ensuring that pharmaceutical products are used appropriately. (JAMA1987;257:2068-2070)