Alcohol consumption is associated to higher risk for thromboembolic disease and heart disease complications produced in part by platelet impairment related to alcohol ingestion. Using the aggregometry technique, in a group of 15 individuals, acute inhibition of platelet aggregation was found in platelet rich plasma under moderate alcohol consumption (13 g) with a blood alcohol concentration of 0,2133 g/L. The inhibition of platelet aggregation was significant (p = 0,05) with epinephrine, ristocetin and ADP (13%; 7,3%; 4,8%; respectively). The inhibitory effect was greater in women than in men. The study demonstrates a flavonoid or tannin independent effect. The importance of low alcohol consumption might be in the prevention of thrombo-embolic processes leading to myocardial infarction or stroke.