Abstract: Cytochrome P450s (CYP450) is a superfamily of phase I metabolic enzymes, which participates in more than 90% of drug oxidation. The induction or inhibition of CYP450s is the main mechanism of drug-drug interaction. In recent years, in vitro metabolism studies conducted through isolated organs, cells, or enzyme systems have developed rapidly, due to their precision and simplicity. Therefore, profiles of the in vitro metabolism studies of traditional Chinese medicines can infer the possible metabolic pathways of drugs, predict the potential drug interactions, and may enhance the rational use of drugs in clinic. This article reviews the in vitro inhibitory effects of traditional Chinese medicine, ingredients, and extracts on the activities of CYP450 enzymes in the liver microsomes, which can provide a reference for further researches on the interaction between Chinese medicine and chemical medicine.