Trans-resveratrol dose limits were evaluated in an animal study. Juan, et al evaluated the toxicity of high doses of trans-resveratrol on Sprague-Dawley male rats. Trans-resveratrol was administered at 20 mg orally per kilogram body weight to rats daily for 28 days, and no treatment-related adverse effects were reported. This dose would be equivalent to a 70-kg person taking 1.4 g of trans-resveratrol per day. Bodyweight, food intake, water intake, blood chemistry and hematology lab work was not affected which suggests that a dose of 20 mg per kilogram per day does not result in toxic adverse events in rats. (15)
Inhibition of platelet aggregation occurred in rabbits treated with resveratrol. Platelet aggregation in hypercholesterolemic rabbits was inhibited both by resveratrol at a dose of 4 mg per kilogram, and when Chinese red wine was given with or without alcohol at 4 ml/kg/day (9). Therefore resveratrol may result in an increased risk of bleeding in patients taking warfarin, Coumadin, heparin, aspirin, and non-steroidal anti-inflammatory drugs.