In this study, 6 genotypes were identified among 549 patients with stroke: CYP2C19*1/*1 (636GG, 681GG) in 191 patients, accounting for 34.79%; CYP2C19*1/*2 (636GG, 681GA) in 233 patients, accounting for 42.44%; CYP2C19*1/*3 (636GA, 681GG) in 30 patients, accounting for 5.49%; CYP2C19*2/*2 (636GG, 681AA) in 65 patients, accounting for 11.84%; CYP2C19*2/*3 (636GA, 681GA) in 29 patients, accounting for 5.28%; and CYP2C19*3/*3 (636AA, 681GG) in 1 patient, accounting for 0.18%. The gene discussed is CYP2C19; the disease is Stroke.