Acetaldehyde is an intermediate by-product in normal carbohydrate metabolism. It is known to psychopharmacologists as the first metabolite of alcohol that is eliminated primarily through oxidation by the enzyme alcohol dehydrogenase in the liver. Acetaldehyde, in turn, is converted to acetate by aldehyde dehydrogenase. Acetaldehyde has pharmacological effects on the cardiovascular system, the liver, monoamine neurotransmitter metabolism, brain function, and behavior. At high levels, it can be toxic, causing headache, facial flushing, nausea and vomiting, tachycardia, headache, sweating, dizziness, and confusion.