Between 1991 and 1992 there was a four-fold increase in drug-related deaths in Glasgow. Comparing records of the drug-related deaths for November 1990-October 1991 and November 1991-October 1992 in Edinburgh and Glasgow, it was found that the increase in Glasgow was statistically significant and that heroin, often mixed with other drugs, which most often included temazepam, diazepam and alcohol, was implicated in the increase in deaths in Glasgow. A number of the deceased had been prescribed temazepam or diazepam. Discussed are the hazards of drug mixing and the possibility that the use of buprenorphine by drug injectors previously had kept the number of overdoses relatively low.