Red rice yeast is a product of the mold "Monascus purpureus" grown on rice, and is common in Asian diets. The yeast contains several compounds collectively known as monacolins, which are known to inhibit cholesterol synthesis. A study has shown that red rice yeast used as a dietary supplement, combined with fish oil and healthy lifestyle changes, may help reduce "bad" cholesterol as effectively as certain commercial statin drugs. Nonetheless, other work has shown it may not be reliable (perhaps due to non-standardization) and even toxic to liver and kidneys.