The redness of the skin after drinking alcohol is due to the lack of an enzyme called acetaldehyde dehydrogenase, which helps metabolize ethanol in the body. About 95% of the alcohol consumed in the body is metabolized by the liver, and the process of metabolism relies on ethanol dehydrogenase and acetaldehyde dehydrogenase. If these two enzymes are active enough in the body, they can quickly break down alcohol into non-toxic and harmless carbon dioxide and water. If there is a lack of acetaldehyde dehydrogenase in the body, the acetaldehyde produced by the decomposition of ethanol cannot be decomposed by acetaldehyde dehydrogenase, and when it accumulates in the body, it can quickly cause blood vessels to dilate. Patients show a generalized redness, especially on the face. Ethanol is a harmful substance that accumulates in the body and damages the body’s organs, damages DNA and may even cause cancer. If you have a red face and red skin after drinking, you should stop drinking in the future.