GHB is currently under legal control in a number of countries. Because of that, pushers and users have switched to two GHB precursors, GBL and 1,4-BD, which can still be legally purchased. GBL has become a growing public health issue because it is relatively cheap and easy to obtain, due to its many industrial uses. Here, we report a case involving a 31-year-old male, who consumed, during a sexual intercourse with more partners (chemsex), a colorless liquid sold as “G”, and shortly after experienced adverse effects never felt before. Segmental hair analysis highlighted exogenous GHB concentration in six segments of 1cm each (range: 27.2–23.9ng/mg). Classic drugs of abuse and some new psychoactive substances were also found in te fist and last hair segment. A toxicological analysis of the liquid was performed and it highlighted the presence of GBL (982g/L) and GHB (0.9g/L), slightly higher than those reported in literature. The high variability of concentration of GBL illegal liquid preparations increases the risk of severe intoxication as in the case here presented.