It has been reported that the presence of homozygote genotypes for alleles ADH2*1 and ADH2*2 in individuals which are also carry of genotype ALDH2 1/1 exhibit a very little increase of acetaldehyde in blood after the ingestion of 0.3-0.5 g/Kg of alcohol, this sample that the acetaldehyde cannot be involved in protection against the alcoholism in individuals with polymorphisms ADH2. In Asian countries it has been reported that the risk of alcoholism with ADH2 ß2ß2 and ALDH2 2/2 is 100 times more under which in individuals with ADH2 ß1ß1 and ALDH2 1/1 3. The gene discussed is ALDH2; the disease is alcohol dependence.