Platelet activation contributes to thrombotic events in cardiovascular disease. Acetylsalicylic acid (ASA) is used in combination with clopidogrel to reduce cardiovascular events. Lysine acetylsalicylate (L-ASA), also inhibits platelet activation with fewer gastrointestinal side effects than ASA. Dual therapy with L-ASA and clopidogrel may result in an antiplatelet effect with fewer side effects. We compared the antiplatelet effect of combined ASA/clopidogrel versus L-ASA/clopidogrel in healthy subjects. Fourteen volunteers (seven men and seven women, aged 25-45 years) received antiplatelet therapy during 14-day periods in the following sequence: 75 mg ASA; 160 mg L-ASA; 75 mg clopidogrel; 160 mg L-ASA plus 75 mg clopidogrel, and 75 mg ASA plus 75 mg clopidogrel. We evaluated platelet aggregation and glycoprotein IIb/IIIa activation. Our results show that administration of L-ASA/clopidogrel is as effective as ASA/clopidogrel combination.