During the year 2017, a research work was carried out at the Department of laboratory diagnostics - Toxicology and Biochemistry U.O.S. of ASP 6 in Palermo. The purpose of this investigation was to perform a second level analysis in order to look for abuse drugs. The sample used consisted of 73 serum tubes, which had previously tested positive for screen- ing tests. The result of the analysis of these samples revealed a false positivity in most cases. From the information gathered through the sampling reports, it appears that the age group with several drivers, who are subject to checks by the traffic police, is the one from 17 to 30 years, with 35 samples analysed (48%). It also emerged that 92% are male and only 8% female. The percentages of substances detected are THC + Cocaine 8%, Cocaine 15% and THC 77%. Thanks to the processing of collected data, a statistic about the consumption of illicit drugs in the city of Palermo has been produced. Through the findings, it was possible to make a comparison with the incidence of abuse of these substances in Italy. Moreover, it was found that Cannabis is the illicit substance mainly used in the Italian territory. Due to the growing increase in drug use on our territory, it is necessary that the methods used for confirmatory analysis be accurate and pre- cise, in order to provide reliable results on the presence of substances of abuse in biological matrices. In fact more and more sophisticated methods and analytical tools are being developed.