The objective of this thesis work was to provide preliminary data on the pharmacokinetic and pharmacodynamic parameters of bufotenin in horses. In a first bibliographical section, the horse exposure factors to bufotenin and the main elements of kinetics and effects of bufotenin in humans were presented. Particular attention was paid to the presence of bufotenin in the cane of Provence (Arundo donax). In a second experimental part, the fate and effects of bufotenin following ingestion of Arundo plant or after oral or intravenous administration of bufotenin were studied. This study shows that bufotenin has not been found in the natural state in our horses of experience, that it is found in urine following ingestion of Arundo cane (400g) or bufotenin administration (0.06 mg/kg oral and 0.025 mg/kg intravenously), that its plasma elimination is rapid, and that no pharmacological effect was observed in horses tested (0.01 to 0.1 mg/kg).