1. A retrospective analysis of 352 consecutive cases of fatal substance overdose that occurred in the Lothian and Borders region of Scotland (LBRS) between 1983 and 1992 (inclusive) is presented. All these cases were subjected to a full forensic autopsy with histological and toxicological studies. 2. The overall male:female ratio is 1.2:1. Males significantly predominate (1.9:1) in the 21-30 year age group, but females significantly predominate (0.7-0.9:1) above the age of 50 years (P < 0.001). A significant progressive alteration in the sex ratio is noted: from 0.7:1 in 1988 to 2.4:1 in 1992 (P < 0.001). 3. Analgesics account for 43.2% of all overdose deaths with narcotic analgesics representing 32.4%. Dextropropoxyphene is the commonest (38.2%) narcotic analgesic and fatal overdoses on it have been increasing since 1989; methadone deaths also showed an increase. Death from heroin overdose fell sharply in 1985. 4. Antidepressants account for 20.2% of deaths (tricyclics representing 19.3%): Amitriptyline is the commonest (75.0%) tricyclic and its use, particularly by female suicides, has been increasing since 1989. Barbiturate poisoning has declined considerably since 1986. 5. Temazepam comprises 65.4% of all benzodiazepines overdose deaths; two-thirds of fatal benzodiazepine abuse involve males. 6. This study once more emphasises that physicians, and especially general practitioners, must prescribe cautiously for their patients. Control through legislation of the sale of non-narcotic analgesics is worth serious consideration.