Adverse drug reactions spontaneously reported by physicians in the hospital and the private practice were compared. All reports were sent to a French Regional Pharmacovigilance Centre over the period of 1 year (1992). Hospital-based physicians reported more adverse reactions and more serious reactions than physicians in private medicine. For both groups of reporters, the skin, central nervous system and digestive tract were the body systems most commonly involved. There were significant differences between the hospital and private practice reports as regards the drugs most frequently involved in adverse drug reactions.