If you turn red every time you have a cold one, you might want to put the bottle down — even if you think you feel fine.

Alcohol flush syndrome (also somewhat problematically referred to as “Asian glow” happens when your body isn’t able to properly digest alcohol. While it’s statistically more likely in Asian populations — hence the somewhat racist nickname for the blush — it can happen to anyone.

“It’s a natural protection phenomena in these individuals that have deficiency,” Daryl Davies, a pharmacologist at the University of Southern California, tells Inverse. “It’s trying to tell them, ‘Don’t be drinking.’”

Basically, alcohol is churned out of your body through your liver with a one-two punch. First, an enzyme in the liver turns alcohol into acetaldehyde. Acetaldehyde is practically a poison, which is treated like any other substance and eventually peed out.

But for many — including Asians and Ashkenazi Jews, among others — the acetaldehyde dehydrogenase, or ALDH2, gene is hopelessly mutated. So acetaldehyde remains in its nasty acetaldehyde state, causing liver damage, ulcers, and cancers of the esophagus and stomach.

See also: This Enzyme Might Explain How Drinking Leads to Alcoholism

All of these horrors are largely invisible, except for that bright blush. That comes from the fact that ALDH2 activates histamines, which flood the system and cause you to turn red, increase your heartbeat, or feel nauseous. It’s kind of like an allergy, and definitely like a wicked hangover.

A lot of people who have alcohol flush reaction regularly want to hide it and keep drinking. While Benadryl might block the histamines and keep the redness under control, it doesn’t stop the larger problem of acetaldehyde building up in your system, silent but deadly.

Instead of wanting to hide it, Davies encourages people to think of it this way: Acetaldehyde is a close cousin of formaldehyde.

“What do we use formaldehyde for?” he asks. “We use it to pickle people.” Yum.

Photos via Flickr / jreifegerste