Healthy volunteers will be consecutively enrolled into 3 arms, each studying one herbal product for 25 volunteers. The design involves taking all 3 of the following combinations: aspirin + placebo, herb + placebo, aspirin + herb, each for a 3-week period, in a randomized order, with 2 weeks of wash-out in between each 3-week period. Platelet function and coagulation profile will be assayed