[From alcohol to liquid ecstasy (GHB)--a survey of old and modern knockout agents. Part 3: gamma-hydroxybutyric acid ("liquid ecstasy")].

Currently, gamma-hydroxybutyric acid (GHB/"liquid ecstasy") is frequently abused as a knockout substance. Its detection and the interpretation of the results present numerous problems which are illustrated by case reports. In this context, hair analysis and the increasing significance of gamma-butyrolactone (GBL) are also discussed.