Why Does Too Much Alcohol Make You Vomit?

It may not feel like it at the time, but this is your brain's way of saving your life.


Consuming too much of just about anything can lead to vomiting, but alcohol is in its own league. This is because there’s an entire section of the brain dedicated to monitoring levels of potentially toxic substances in the body and purging them if necessary, but how does this system work, and why is booze at the top of its hit list?

According to Dr. Aaron White, senior scientific advisor at the American National Institute of Alcohol Abuse and Alcoholism, a region of the brain known as the area postrema “triggers vomiting when the amount of alcohol it detects reaches a critical level.” What exactly that critical level is depends on the person and their alcohol tolerance. A blood alcohol content of 0.4 or higher (which, depending on the person’s weight and sex, can mean anywhere between eight and 11 drinks) is generally considered toxic and potentially deadly, and therefore likely to lead to a sudden stumbling rush to the bathroom.

If you find yourself starting to heave long before that eight cocktail limit, White adds that there are a few other reasons alcohol may disturb your stomach. The first, he says, “is that vomiting often follows irritation of the gastrointestinal tract. For some people, that could be a result of too much carbonation, while for others it could be a result of mixers that are too sweet or too bitter.” In other words, it’s best to steer clear of neon-coloured cocktails and bubbly beer if you’re prone to post-party puking.

The second reason is a side effect of what White calls “alcohol-induced motion sickness,” otherwise known as “the spins.” That’s why we often don’t feel the urge to vomit until after we’ve already hopped into bed, as this is typically the moment the spins take effect.

As far as prevention goes, it’s always a good idea to fill your stomach with carbohydrate-rich foods—aka, everyone’s favourite drinking foods, like pizza, fries and sandwiches—before drinking, to slow the rate at which your body absorbs the alcohol. Not only will this help prevent irritation of your gastrointestinal tract, it will keep the amount of alcohol in your bloodstream from spiking. Also, while it’s tempting to pop a few painkillers to relieve your pounding headache the morning after, they often have the opposite effect on the stomach, so it’s generally best to opt for an antacid instead.

Just remember, next time you end up facing the porcelain after a long night out, this is your body’s way of saying you can’t drink as much as you think you can.