comparison of antiplatelet activity of garlic tablets with cardio-protective dose of aspirin in healthy volunteers: a randomized clinical trial

objective: some of the adverse effects of aspirin including peptic ulcers, gastrointestinal bleeding and aspirin resistance compelled researchers to find a suitable alternative with fewer adverse effects. in this clinical trial, we aimed to find the effective antiplatelet dose of garlic. materials and methods: this randomized controlled clinical trial (rct) was conducted on 62 healthy volunteers of 20-50 years old. all volunteers used 80 mg aspirin per day for 1 week and at the end of this time, platelet aggregation (pa) induced by 4 agonists acting in aggregation pathway including adenosinediphosphate (20 μmol/l), epinephrine (20 μmol/l), collagen(0.19 mg/ ml) and arachidonic acid (0.5mg/ ml) was measured by light transmittance aggregometry (lta) in all participants. after one month washout period, volunteers were randomized into 3 groups and each received 1, 2 or 3 garlic tablets (1250 mg) a day for 1 month. after one month, pa was examined in all groups. results: the mean ±sd of the age of all volunteers was 28.60 ± 9.00 years. in addition, 52.00 % of our volunteers were male and 48.00% of them were female. garlic tablet didnot have significant effect on pa at any dose. however, 30% of volunteers in the group that used 3 garlic tablets/day reported adverse effect (i.e. bleeding). no significant association between sex, age and pa was observed. conclusion:  in this study, we were unable to determine the effective anti-platelet dose of garlic which that could be equal to that of aspirin anti-platelet activity, as assessed lta method.