In 2001, guidelines concerning cannabis were issued by the Group of Forensic Chemistry of the Swiss Society of Forensic Medicine. These guidelines deal with the sampling of Cannabis plants and their processing before analysis. Some recommendations are also suggested for the determination of Delta(9)-tetrahydrocannabinol (Delta(9)-THC). In this paper, the biosynthetic pathway of Delta(9)-THC is presented and the putative ecological function of the cannabinoids discussed. The taxonomy and botany of the hemp plant are also considered. The influence of age, sex, and plant part on the accumulation of Delta(9)-THC is discussed. The need for criteria aimed at the distinction between fiber hemp and cannabis belonging to the drug type is especially emphasized. The current Swiss situation and legislation are briefly presented. Furthermore, the sampling of cannabis material, its processing and analysis are described, alternative strategies for the characterization of hemp exhibits are also presented.