Background. The aim of the study was to map the prevalence of alcohol and other psychotropic substances in deceased participants of traffic accidents in the Czech Republic. Methods and Results. The studied sample included persons autopsied in the departments of forensic medicine and forensic toxicology that died during traffic accidents and were toxicologically tested in 2003. Case definition involved alcohol cases with blood alcohol concentration (BAC) 0,2 g/kg and higher, with cannabis, detections of active THC metabolites only were taken into account; in cases where volatile substances (solvents) were detected we included into the definition only cases with substances not produced post mortem or in some physiological or pathological statuses. We identified 554 cases of whom 440 (79.4 %) were males and 114 (20.6 %) were females. 35.5 % were in the age group 20 – 34 years. The sample has been classified into 4 categories (average age, % of males): pedestrians (45.4, 76.2), bicyclists (51.1, 82.0), drivers (36.3, 91.2) and others (36.1, 66.2). Alcohol was tested in 548 cases, 214 (39.1 %) of those were found positive. 380 cases were tested for other psychotropic substances than alcohol; samples taken from 25 bodies (6.6 %) were found positive for at least for one of these substances. 8 cases were positive both for alcohol and some other psychotropic substance – i.e. 3.7 % out of 214 cases positive for alcohol were positive for other substance and 32.0 % out of 25 cases positive at least for any other psychotropic substance were alcohol-positive. When focusing our analysis at the active participants of road traffic accidents only - pedestrians, bicyclists and drivers (altogether 397 cases) – we have found alcohol to be tested in 394 cases, out of which 158 (39.1 %) were positive; as for other psychotropic substances, 314 cases were tested and 23 (7.3 %) were positive at least for one of them. 7 cases were found positive for alcohol and other psychotropic substance simultaneously; this represents 4.4 % out of 158 cases positive for alcohol and 30.4 % out of 23 cases positive at least for one psychotropic substance other than alcohol. Average BAC in active participants of road traffic accidents positive for alcohol were 1.81 ‰, (1.98 ‰ in pedestrians, 1.78 ‰ in bicyclists and 1.64 ‰ in drivers). Prevalence of either alcohol or any other psychotropic substances is the lowest in the category of drivers – with the exception of active cannabinoid compounds. Alcohol was by far the most prevalent psychotropic substance, also cannabis, benzodiazepines and stimulants have been found in not negligible frequencies. Conclusions. The study confirms high prevalence of alcohol influence in deceased participants of traffic accidents. Prevalence of other psychotropic substances is lower by order, but it becomes also significant.

        Key words: drugs, alcohol, illegal drugs, traffic accidents, BAC.