Cannabidiol (CBD) is a phytocannabinoid present in cannabis, obtained either by extraction from the plant or by synthesis. The latter has the advantage of being pure and contains few impurities, unlike CBD of plant origin. It is used by inhalation, ingestion or skin application. In France, the law stipulates that specialties containing CBD may contain up to 0.3% of tetrahydrocannabinol (THC), the psychoactive principle of cannabis. From an analytical point of view, it is therefore important to be able to quantify the two compounds as well as their metabolites in the various matrices that can be used clinically or forensically, in particular saliva and blood. The transformation of CBD into THC, which has long been suggested, appears to be an analytical artifact under certain conditions. CBD is not without toxicity, whether acute or chronic, as seems to attest to the serious adverse effects recorded by pharmacovigilance during the experiment currently being conducted in France by the Agence Nationale de Sécurité du Médicament et des Produits de Santé. Although CBD does not seem to modify driving abilities, driving a vehicle after consuming CBD containing up to 0.3% THC, and sometimes much more in products bought on the internet, can lead to a positive result in screening and confirmation tests by law enforcement agencies, whether salivary or blood tests, and therefore lead to a legal sanction.