摘要In vitro models of human colon carcinoma cell line(Caco-2 cell monolayer) and human intestinal bacteria were used to investigate the intestinal transport and biotransformation of resibufogenin and cinobufagin in Chan Su by HPLC/APCI-MS<'n>. The experimental results of Caco-2 cell monolayer demonstrate that the apparent permeability cocfficients(P<,app>) of resibufogenin and cinobufagin are higher than 10<'-6> cm/s, which indicates that both resibufogenin and cinobufagin have a good absorption in the small intestine. And the biotransformation result of human intestinal bacteria shows that resibufogenin has been transformed to 3-epiresibufogenin and cinobufagin has been transformed to 3-epicinobufagin, deacetyicinobufagin and 3-epideacetycinobufagin, respectively.