Aldehyde dehydrogenase 1A1 (ALDH1A1) is a member of a superfamily of detoxification enzymes found in various tissues that participate in the oxidation of both aliphatic and aromatic aldehydes. The human ALDH1A1, which is tetrameric and predominantly of cytosolic origin, functions mainly in acetaldehyde and neurotransmitter metabolism. It is also reported to play a major role in the production of retinoic acid, which is important for gene expression and tissue differentiation, and also in cyclophosphamide detoxification. ALDH1A1 is found in various tissues, including the central nervous system (CNS), with highest levels in the liver. In the brain, ALDH1A1 participates in the metabolism of catecholamines including dopamine (DA) and norepinephrine, and is uniquely expressed in a subset of dopaminergic (DAergic) neurons in the ventral mesencephalon where it converts 3,4-dihydroxyphenylacetaldehyde, a potentially toxic aldehyde, to 3,4-dihydroxyphenylacetic acid, a non toxic metabolite. ALDHA1 has been implicated in the development of alcohol dependence and other alcohol-use disorders, alcohol-induced flushing and sensitivity to alcohol.