To investigate the effects of different extracts of Rhizoma Coptidis on cardiotoxicity in rats.SD rats were divided into five groups and ig treated with purified water,ethyl acetate extract,dichloromethane extract,petroleum ether extract and water extract,respectively,25 g crude drug/kg for 30 days.After 30 days,biochemical indexes and heart weight were measured,organ coefficient was calculated,and CK and LDH levels in serum were measured.UPLC-Q-TOF-MS was used to analyze the difference of components in different extracts from Rhizoma Coptidis.Compared with the control group,the LDH level in rat serum treated with the ethyl acetate extract was significantly increased (P<0.05),and the heart weight and organ coefficient were both significantly increased.A total of 34 kinds of alkaloids and flavonoids were detected in extracts by UPLC-Q-TOF-MS,of which 21 compounds were common in each extract fraction,one compound was unique in petroleum ether extact fracion,two compounds uniquely existed in dichloromethane extact fracion,one compound was unique in ethyl acetate extact fraction and two compounds were unique in water extact fraction.It is suggested that ethyl acetate extract had a significant cardiotoxic effect on rats,and 2′,4,4′-trihydroxy-6′-methoxydihydrochalcone may be its cardiotoxic active component.However,dichloromethane extract,petroleum ether extract and water extract had weak cardiotoxicity.