Since acetaldehyde is a toxic metabolite of ethanol, its accumulation causes several acute and chronic diseases related to the excessive intake of alcoholic beverages. Aldehyde dehydrogenases (ALDHs) play an important role in the metabolism of not only exogenous aldehydes, but also endogenous ones including acetaldehyde. Among the ALDH family, ALDH2 mainly contributes to acetaldehyde elimination. This paper reviews the function of ALDH2 as well as auxiliary ALDHs in the ethanol metabolism. This paper also summarizes the regulation of the total ALDH activity by certain food chemicals, providing implication for their therapeutic potential against alcohol-related diseases.