Abstract: Objective To assess antiplatelet efficiency for patients with cytochrome P450 polymorphisms using Clopidogrel. Method A comprehensive electronic search was carried out and 8 independent studies with a maximum of 1 538 cases and 4 413 controls were analyzed using the Cochrane Collaboration’s RevMan 5.0 software. Results Eight studies met the included criteria. There were statistically significant differences between loss-of-function CYP2C19 （GA or AA） and wild genotype（GG） for the response status to Clopidogrel: the fixed effects odds ratio（OR） was 0.23 95% confidence interval（CI） 0.13 to 0.40; for the plasma concentration levels of Clopidogrel: the random effects MD was -17.38（95% CI -25.59 to -9.16）; for the platelet reactivity index of Clopidogrel: the random effects MD was 12.87 95% CI 8.48 to 17.26; for the definite stent thrombosis: the fixed effects OR was 3.68 （95% CI 2.17 to 6.24）; for death of patients: the fixed effects OR was 3.68 （95% CI 1.82 to 7.43）; however, there were no statistically significant differences between GA or AA and GG for myocardial infarction （MI）: the fixed effects OR was 1.25 95% CI 0.96 to 1.63. Conclusions The presence of the loss-of-function CYP2C19 is associated with low plasma concentration, response status and antiplatelet efficacy of Clopidogrel and indicators of efficacy except for MI in patients using clopidogrel as antiplatelet agent.