Self-medication can be defined as obtaining and consuming one (or more) drug (s) without the advice of a physician either for diagnosis, prescription or surveillance of the treatment. Self-medication accounts for around 5 to 10 per cent of drug sales in France. There are few data on side effects of self-medication in France. The side effects of drugs taken by self-medication and reported to the Midi-Pyrenees drugs surveillance centre between January 1993 and June 1996 were investigated in the present study. There were 65 reports, mainly in women (58 per cent), i.e. around 2 per cent of the reports to the regional drugs surveillance centre. The most frequent side effects are neurological (32 per cent: mainly headache, vertigo, agitation, etc.), dermatological (18 per cent, mainly allergy), hepatic (10 per cent), digestive (7 per cent, mainly diarrhoea). There were 10 cases of anaphylactic shock and/or Quincke oedema. The drugs most frequently involved were analgesics and non-steroidal anti-inflammatory drugs (47 cases), neuropsychotropic drugs (7 cases), dermatological drugs (6 cases) or otorhinolaryngological drugs (6 cases).... 'Serious' side effects occurred in 40 per cent of the cases including 3 deaths. 'Severe' side effects were observed in 77 per cent of the reports. This study shows that the side effects of self-medication are relatively frequent and can be serious. They occurred more often in women than in men, mainly with analgesic and anti-inflammatory drugs. These data permit a better analysis of the risk/benefit ratio of self-medication. Drug surveillance studies of self-medication must be developed.