Aim To investigate the effect of SM-1 on seven main cytochrome P450(CYP450)in human liver microsomes.Methods Substrate or SM-1 was incubated with human liver microsomes for 30 min in vitro,and divided into control group and experimental group.The effects of SM-1 on the main phase I metabolic enzymes in human liver microsomes was detected by HPLC.Phenacetin,bupropion,paclitaxel,tolbutamide,omeprazole,dextromethorphan,testosterone were investigated as probe drugs.Results Inhibition rate of SM-1 on the classical substrate of human liver microsomal CYP was 0.05%,3.37%,0.08%,2.07%,4.20%,-0.15%and 10.84%,respectively.Conclusions SM-1 may have inhibitory effect on CYP3A4.Attention should be paid to the interaction of clinical drug induced by CYP enzyme inhibition.