Objective To assess the effects and safety of vasodilators for sudden sensorineurial hearing loss (SSHL). Search strategy Electronic databases: MEDLINE from 1966, EMBASE from 1974, the Cochrane Controlled Trials Register, Chinese Bio-medicine Database from 1989. Hand search: Five kinds of Chinese otolaryngology journals were searched. Literature references were checked intensively. Selection criteria Randomized controlled trials comparing vasodilators with placebo or other drugs in patients with SSHL. Data collection and analysis At least two reviewers independently assessed trials quality and extracted data. Main results Thirteen trials with 1 155 patients were eligible and included in the systematic review. Ten of the trials were from developed countries and them were from P. R. China. None of the four trials showed that the effects of vasodilators were better than placebo for SSHL. None of the seven trials showed that the effects of one kind of vasodilators were better than that of the other vasodilators. Two trials showed that other drugs, such as batroxobin and hypaque,were probably better than some vasodilators (dextran, papaverine, 654-2, danshen). Eight trials reported the side effects of vasodilators, such as pruritus, allergy, etc. Reviewers’ conclusions Base on the systematic review of current eligible randomized controlled trials, there is no evidence to prove that vasodilator therapy is better than placebo or other therapies for SSHL, or the effects of one kind of vasodilator are better than that of the other vasodilators. We can’t draw a reliable conclusion about the effects of vasodilators for SSHL at the moment. And we must pay attention to their potential adverse reactions.