Someone with a congenital deficiency for the acetaldehyde dehydrogenase enzyme, or too young to express adult levels of it, will definitely feel bad after a dri

Someone with a congenital deficiency for the acetaldehyde dehydrogenase enzyme, or too young to express adult levels of it, will definitely feel bad after a drink. Ethanol metabolizes to acetaldehyde, which is a chemical that causes several unpleasant symptoms. Among these is the so-called "Asian blush". (Asians have a higher incidence of acetaldehyde dehydrogenase deficiency.) Any amount of alcohol you drink in excess of your liver's ability to express acetaldehyde dehydrogenase will cause damage. If you get a hangover, it was too much.