In Egypt the disease seneciosis affects most species of domestic livestock and several cases of fatal Senecio poisoning, particularly in chidren, have been reported. The main alkaloids isolated from the plant proved to be senecionine, seneciphylline, senkirkine, retrorsine, angelyltetronocine and further alkaloid (Probably an isomer of senkirkine). Fractionation of the alkaloids was carried out by column chromatography using Al203, followed by preparative TLC (alumina).Identification of these alkaloids was carried out by m. p., TLC, IR, MS, NMR, GLC and HPLC as well as preparation of N-oxides and hydrolysis.The acute oral and intraperitoneal toxicity tests in Rodent species for the total alcoholic extract were done. The pharmacological properties of senecionine HCI was determined using in vitro isolated tissue or organ preparation. Some experiments on intact anaesthetized animal were done.