Red yeast rice is a Chinese product that has been used for centuries in food as a preservative, flavoring and coloring agent. It makes Peking duck red, for example, and is used in red rice vinegar. It also has been used in traditional Chinese medicine for indigestion and to promote blood circulation.
Red yeast rice can lower cholesterol. It contains some compounds related to statin-type cholesterol-lowering drugs such as lovastatin (Mevacor).
A recent study in China shows that red yeast rice can nearly halve the risk of a second heart attack (American Journal of Cardiology, June 15, 2008).