Previous studies with small sample size have shown that cilostazol can reduce the risk of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study was to determine whether cilostazol is effective in patients with aneurysmal SAH. Studies investigating the effect of cilostazol in patients with aneurysmal SAH were identified using Embase.com without language or publication-type restrictions. We used the random-effect model to combine data. Pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated. Two randomized controlled trials and two quasi-randomized controlled trials with a total of 340 patients were included. The incidence of symptomatic vasospasm (RR = 0.47; 95% CI, 0.31-0.72; p < 0.001), severe vasospasm (RR = 0.48; 95% CI, 0.28-0.82; p = 0.007), vasospasm-related new cerebral infarctions (RR = 0.38; 95% CI, 0.22-0.67; p = 0.001), and poor outcome (RR = 0.57; 95% CI, 0.37-0.88; p = 0.011) were significantly lower in the cilostazol group. The numbers needed to treat for these outcomes were 6.4, 6.3, 5.7, and 5.4, respectively. Mortality rate differences between the two groups were insignificant. No statistical heterogeneity was found for all outcomes. These results show that cilostazol can decrease the incidence of symptomatic vasospasm, severe vasospasm, vasospasm-related new cerebral infarctions, and poor outcome in patients with aneurysmal SAH. (C) 2013 Elsevier B.V. All rights reserved.