Epidemiological evidence indicates that recent heavy alcohol consumption increases the risk for all major types of stroke, whereas light-to-moderate alcohol intake is associated with a decreased risk of ischemic stroke. Although heavy drinking elevates blood pressure, there is no firm evidence to indicate that alcohol consumption causes the formation of aneurysms, microaneurysms or other lesions in human arteries. Alcohol has been reported to precipitate vasoconstriction and rupture of small cerebral arteries in experimental animals. Alcohol-induced neck trauma has been shown to precipitate traumatic strokes, and alcohol-induced cardiac arrhythmias have been observed in patients with embolic brain infarction. The effects of alcohol on hemostasis, fibrinolysis and blood clotting are variable and could either prevent or promote the occurrence of strokes. The antiatherogenic effects of regular light-to-moderate alcohol consumption could be mediated by inhibition of low-density lipoprotein oxidation, and by elevated estrogen levels.