This article aims to review general procedures for sampling of routinely collected as well as on alteative samples that may provide additional information regarding intoxication. These approaches may be applied whenever sample collection for clinical and forensic toxicology is required and should be considered as general guidelines that must be adapted to each specific case. It is expected that this article will help toxicologists and other forensic experts to accomplish their mission, since the toxicological result is first influenced by the quality and quantity of the sample available for analysis. These guidelines were approved by the European Council of Legal Medicine.