The redness happens because of a genetic issue in the way your body handles alcohol. Normally, your liver breaks down alcohol in two steps:

1. Alcohol dehydrogenase (ADH) turns alcohol into acetaldehyde, a toxic substance.
2. Aldehyde dehydrogenase 2 (ALDH2) then breaks down acetaldehyde into harmless acetic acid and water.

However, some people are born with a defective ALDH2 enzyme due to a gene mutation (called ALDH2*2). When this enzyme doesn’t work properly, acetaldehyde builds up — causing your blood vessels to expand and your skin to turn red, especially on the face, neck, and upper body.

This condition is most common among East Asian populations — around 30–50% of people of Chinese, Japanese, or Korean descent have this gene variant.

It also appears in some people of Jewish ancestry, particularly Ashkenazi Jews. Globally, that’s about 540 million people, or 8% of the world’s population, who experience alcohol flush reaction.

Because of this, it’s often called “Asian flush” or “Asian glow”, though doctors now prefer the term “alcohol intolerance.”

Redness is just one sign. When acetaldehyde builds up, it triggers allergy-like reactions such as:

• Headaches and nausea
• Fast or irregular heartbeat
• Dizziness and low blood pressure
• Runny nose or nasal congestion
• Feeling hot or uncomfortable

These symptoms can appear within 30 minutes of drinking — sometimes even faster.

The redness might fade after a few hours, but the health risks are serious. When your body can’t break down acetaldehyde, the toxic buildup can lead to long-term damage.

1. Higher Cancer Risk
People with ALDH2 deficiency who continue to drink face a much higher risk of esophageal cancer — one of the deadliest cancers linked to alcohol. The more you drink, the higher your risk. Research also connects it to stomach, head and neck, and skin cancers.

2. Heart and Blood Vessel Problems
Studies show a connection between alcohol intolerance and a higher chance of heart disease and stroke, especially in those who drink often.

3. Brain and Memory Issues
New research from Stanford Medicine found that the ALDH2 mutation might also raise the risk of Alzheimer’s disease because toxic byproducts can damage brain cells over time.

4. Liver and Bone Health
ALDH2 deficiency is linked to liver problems and even weaker bones (osteoporosis), especially in people who continue drinking regularly.

The only true way to stop alcohol flush is to drink less or not at all. It’s not about avoiding embarrassment — it’s about protecting your health.

Avoid These Common Mistakes
Some people try to hide the redness by taking antihistamines like Pepcid AC or Zantac. While these may reduce flushing temporarily, they don’t stop acetaldehyde buildup. This means the toxin still damages your body — and because the warning signs are masked, you may end up drinking more, increasing your cancer risk.

Safer Drinking Tips
If you choose to drink:

• Pick low-alcohol beverages like beer or wine spritzers
• Drink slowly and in moderation
• Eat before drinking, especially high-fat foods to slow absorption
• Stay hydrated by alternating water with alcohol

Not necessarily. Rosacea is a skin condition that can also cause facial redness, but it’s unrelated to ALDH2 deficiency. Alcohol may trigger rosacea flare-ups, but the underlying cause is different. Some people might have both, which can make redness worse.