RationaleRankinidine belongs to the humantenine‐type alkaloids isolated from Gelsemium. Currently, the mechanism behind the toxicity differences of rankinidine has not been explained. In this study, our purpose was to elucidate the major in vitro metabolic pathways of rankinidine and to compare the formation of metabolites of rankinidine in human (HLMs), rat (RLMs), goat (GLMs) and pig (PLMs) liver microsomes.MethodsThis is the first study to compare the in vitro metabolism of rankinidine with high‐performance liquid chromatography/quadrupole...