Senecionine (Senecionan-11,16-dione, 12-hydroxy-) is a pyrrolizidine alkaloid isolated from Senecio vulgaris. Senecionine is toxic to animals and humans. In Vitro: Pyrrolizidine alkaloids (PAs) are considered to be one of the most hepatotoxic groups of compounds of plant origin and are present in about 3% of the world's flowering plants. Most PAs represent a considerable health hazard to both livestock and humans through the consumption of plants and PA-contaminated products such as milk, honey, herbal teas, and medicines^[1]. In Vivo: Upon intravenous administration and oral administration of Senecionine and Adonifoline, significant differences in pharmacokinetics were observed, with the Senecionine and Adonifoline being absorbed fast with lower bioavailability and being quickly metabolized to PA N-oxides and hydroxylation products of PAs or their N-oxides^[1]. Senecionine fails to stimulate epoxide hydrase, it diminishs the activity of glutathione-s-transferase, aminopyrine demethylase and AHH^[2]. Twice-weekly injections of a third constituent, senecionine, beginning on Day 12 or later, results in premature deliveries in three of seven rats, and the pups from all litters are stillborn or die shortly after birth^[3].