in research:NIH study uncovers probable mechanism underlying resveratrol activity, February 2, 2012 News Release - National Institutes of Health (NIH)

"....Chung noted that because resveratrol in its natural form interacts with many proteins, not just PDEs, it may cause not-yet-known toxicities as a medicine, particularly with long-term use. He added that the levels of resveratrol found in wine or foods are likely not high enough to produce significant health benefits or problems. Convincing clinical studies in humans have used about 1 gm of resveratrol per day, roughly equal to the amount found in 667 bottles of red wine....."