Because there is little information about the safety of red yeast rice when it is used over an extended period of time, it is best to limit its use to short term.

People who are at risk for liver disease, or currently have liver disease, should not take red yeast rice because, similar to prescription cholesterol lowering medications, red yeast rice may affect liver function.

Those who consume more than two alcoholic beverages per day, have a serious infection or physical disorder, or have undergone an organ transplant are also advised to avoid red yeast rice.

Red yeast rice should not be taken with cholesterol-lowering (statin) medications known as HMG-CoA reductase inhibitors (such as atorvastatin, lovastatin, fluvastatin, simvastatin, pravastatin, cerivastatin), because it may enhance the effect of these medications, thereby increasing the risk of liver damage.