Aristolochia is a large plant genus with over 500 species. Collectively known as birthworts, pipevines or Dutchman's pipes, they are the namesake of the family (Aristolochiaceae). They are widespread and occur in the most diverse climates. Some species, like A. utriformis and A. westlandii, are threatened with extinction. Aristolochia contorta commonly named Ma Dou Ling is a perennial member of the Aristolochia genus in the family Aristolochiaceae.
Fifteen compounds were isolated from the dry fruit of A. contorta, which were six aristolochic acids: aristolochic acid I, aristolochic acid III a, aristolochic acid IVa, aristolochic acid II, aristolochic acid III and aristolochic acid VIIa. Three aristolactams: aristololactam I, aristololactam II and aristololactam IIIa. Three phenolic acids syringic acid, vanillic acid and p-coumaric acid. Three other type compounds: pentacosane acid, beta-sitosterol and daucossterol.