Did you ever wonder what causes a hangover?
The liver is responsible for metabolizing all alcohol a person consumes, but it doesn't always work fast enough to keep up with consumption.
There are three steps to metabolizing alcohol. First, Ethanol is converted to Acetaldehyde by Alcohol Dehydrogenase. Next, Acetaldehyde is converted to Acetic Acid by Acetaldehyde Dehydrogenase. Actetic acid is then excreted by the body.
As the liver works to break down alcohol it often becomes backed up because there is a limited amount of Acetaldehyde Dehydrogenase in the liver, leading to a build up of Acetaldehyde in the blood. Acetaldehyde causes headaches, nausea, hypotension and vomiting - a hangover.
Interestingly, Ethylene glycol (antifreeze) and Methanol are metabolized similarly. However, accidental ingestion and subsequent build up of their breakdown products causes kidney and eye damage. Alcohol is used to combat this by competing for the available enzyme, thus limiting their breakdown.