The methanolic extract of the aerial portion of Chenopodium chilense Schrad., used in Chilean traditional medicine as a remedy for stomach-ache, has been found to exert the major spasmolytic activity in acetylcholine contracted rat ileum. This extract, with a complex flavonoid patterns on thin layer chromatography (TLC) analysis, is practically non-toxic both for rats and brine shrimp Artemia salina in acute toxicity test.