After a night of drinking, it is not uncommon to experience a hangover, which can draw a distinct relationship between alcohol and nausea. While the feeling of nausea after drinking alcohol can be caused by a few different conditions or combination of conditions, the most common connection between alcohol and a feeling of nausea occurs in the stomach: as alcohol enters the stomach and affects the stomach's lining, the person will experience nausea.
Another connection between alcohol and nausea is dehydration. As alcohol circulates through the body, ethanol promotes dehydration by increasing urine production. This process can cause headaches and dry mouth, which can, in turn, cause nausea in some people. Those conditions can combine to make a person lethargic, achy, and nauseated.
Of course, alcohol and nausea can also go hand in hand before the hangover begins. While consuming alcohol, it is important to remember that large quantities of liquid or food — not just alcohol — can cause illness, nausea, and other severe discomfort. If the body recognizes that it is receiving too much liquid all at once, the stomach may reject more fluid, thereby causing nausea and vomiting. This same rejection can occur when too much of any substance is ingested in a short period of time.
Other variables that may cause a connection between alcohol and nausea might be found in the ingredients of certain alcohols. Many types of alcohols are made with different ingredients to give a certain flavor or potency, and these ingredients may cause an allergic reaction or other irritation in some users. For example, many beers contain gluten, which is a common food allergy for many people. If a person with a gluten allergy ingests certain beers, that person may become ill with nausea or other severe or minor conditions.
Since alcohol can cause a loss of equilibrium in the human brain, causing a sensation of dizziness or extreme motion — sometimes called the spins — nausea may result from the perceived spinning motion after too much alcohol is consumed. Nausea is common in people who experience vertigo or motion sickness; when large amounts of alcohol are consumed, the brain can experience perceived motion, and the person may experience nausea as a result.
In many of the cases mentioned above, nausea can lead to vomiting. Vomiting can be potentially dangerous, as it is possible to choke on the vomit expelled through the mouth, causing severe discomfort or even death.