ObjectivesTo systematically review the efficacy of folic acid supplementation in the primary prevention of stroke among patients with H-Type hypertension.MethodsPubMed, EMbase, The Cochrane Library, WanFang Data, CNKI, VIP and Sinomed databases were electronically searched to collect randomized controlled trials (RCTs) of folic acid supplementation in the primary prevention of stroke among patients with H-Type hypertension from inception to April, 2020. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software and Stata 12.0 software.ResultsA total of 12 RCTs involving 18 170 participants were included. The results of meta-analysis showed that H-Type hypertensive patients who received folic acid and antihypertensive had a significant low risk of stroke (RR=0.34, 95%CI 0.21 to 0.55, P<0.000 1) compared with patients who received antihypertensive alone. In the stratified analyses, folic acid >2 mg/d (RR=0.27, 95%CI 0.14 to 0.51, P<0.000 1) and ≤2 mg/d (RR=0.36, 95%CI 0.20 to 0.65, P=0.000 8) both could reduce the risk of stroke. Enalapril folic acid tablets (RR=0.35, 95%CI 0.16 to 0.77, P=0.009) and free combinations of folic acid and antihypertensive drugs (RR=0.29, 95%CI 0.18 to 0.47, P<0.000 01) could lower the incidence of stroke.ConclusionsCurrent evidence shows that the folic acid supplementation significantly reduce the risk of stroke among patients with H-Type hypertension. Enalapril folic acid tablets and free combinations of folic acid with antihypertensive drugs both play an important role in stroke prevention. There is no significant dose-response relationship between dosage of folic acid and prevention of stroke. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify above conclusions.