The use of chemical substances affecting the human psyche is as old as human history. Drug abuse is a problem which can be examined from many aspects - medical, legal, social, criminological, etc. The heart of the problem is the spread of drugs and related damage to young people, at the expense of material interests of the people involved in the system of distribution. In Bulgaria in the years after 1989 drug problem became a current issue. This work describes the results from the analysis of objects collected as evidence at crime scenes in cases of deaths of drug addicts or drug intake by living persons. The samples, after liquid / liquid extraction or directly dissolved in methanol, were analyzed by using GC with NPD detector and composition of the mixture was determined by comparison of retention times of the individual components using standard substances. After 2012, mass spectrometric identification was used. Substances and impurities, established in "street" heroin and other evidence for a period of 12 years, are summarized here. The following substances and narcotic opium alkaloids were found in most of the examined objects: acetyl codeine, 6- mono acetyl morphine, caffeine, heroin, papaverine, noscapine (narcotine), morphine and impurities: phenobarbital, diazepam, paracetamol.