Abstract: The preliminary chemical composition of Senecio scandens was examined by subentry extracting trial in cuvette, systemic extracting trial and round paper chromatographic trial, and pyrrolizidine alkaloids (PAs) in S. scandens and in antimicrobial and analgesic part extracted from S. scandens were analysed by test of silica gel thin layer chromatography (TLC) sprayed with Ehrlich reagent. The results showed that S. scandens mainly contained flavones, anthraquinones, phenolic substances, cardiac glycosides, amino acids, tannic materials, saponins, organic acids and alkaloids, that S. scandens did not contain cyanogenic glycosides, polypeptides, proteins, lactones, lipins and volatile oils, and that S. scandens did contain PAs but there was no PAs detected in the antimicrobial and analgesic part extracted from S. scandens.