If you have a pattern of suddenly feeling very sick after consuming alcohol, you may wonder if you developed sudden onset alcohol intolerance. You may also wonder if such a condition is possible. Sudden alcohol intolerance is a real condition, but it can sometimes be confused with other related conditions such as allergies or drug interactions with alcohol.

Symptoms of Alcohol Intolerance

Symptoms of alcohol intolerance most often develop rapidly. Sometimes they can occur immediately following drinking alcohol. Symptoms can be mild or severe and may include:

  • Flushed skin
  • Nausea
  • Fast heartbeat
  • Low blood pressure
  • Headache
  • Feeling very tired
  • Stuffy nose

Even if you know alcohol makes you feel poorly, it can sometimes be hard to figure out the root cause of the problem. The symptoms may be caused by a few different conditions:

  • Having an alcohol allergy: An allergy to alcohol itself is very rare as the body naturally produces small amounts of alcohol on its own.
  • Having an allergy to a specific ingredient in your drink: Alcoholic drinks may contain allergens, which can range from wheat to egg proteins. Allergens in your drink may be the cause of your symptoms. You may be able to drink alcohol if you can avoid the specific ingredient that makes you feel unwell.
  • Medication interacting with alcohol: Several drugs may make you feel very sick when taken with alcohol. You can feel sick due to a drug interaction with alcohol. Speak to your doctor or pharmacist to make sure that your drugs are safe to take with alcohol.
  • Alcohol intolerance: Having an alcohol intolerance is a genetic condition that means your body can’t process alcohol easily. With this condition, you have an inactive or less-active form of the chemical that breaks down alcohol in your body.

Causes of Alcohol Intolerance

The main cause of alcohol intolerance is a problem in how the body breaks down alcohol. When you drink alcohol, your liver first breaks down alcohol into a toxic chemical called acetaldehyde. Doctors have found that acetaldehyde can cause cancer and make you feel very sick. For this reason, your body usually breaks it down into non-toxic byproducts very quickly. Your body uses a chemical called aldehyde dehydrogenase, or ALDH2, to break down acetaldehyde.

When broken down, acetaldehyde can’t hurt you. However, in some people, ALDH2 does not work correctly, resulting in alcohol intolerance. Sometimes, high levels of acetaldehyde can even lead to an asthma attack. Research has shown that up to half of asthma patients in Japan have had an attack due to high levels of acetaldehyde that their bodies can’t break down.

Doctors have found that a problem with ALDH2 is genetic. Therefore, it is likely that your family members are at risk for the same problem. The main risk factors for having a problem with ALDH2 is being of East Asian descent, especially:

  • Chinese
  • Korean
  • Japanese

Complications of Alcohol Intolerance

Even if you only have mild symptoms of alcohol intolerance, you should avoid alcohol. Research has shown that some people with mild symptoms of intolerance can get used to the symptoms of excess acetaldehyde in their bodies. However, acetaldehyde is still highly toxic and can cause cancer. For this reason, doctors found that there is a high rate of esophagus cancer in East Asian patients with mild alcohol intolerance who drink alcohol. This type of cancer is very deadly. The top five-year survival rate is only 31%. East Asian patients with mild alcohol intolerance are up to 10 times more likely to develop this type of cancer if they drink alcohol.

Treatment for Alcohol Intolerance

Unfortunately, the only treatment for alcohol intolerance is avoiding alcohol. No drug will help you avoid the symptoms of alcohol intolerance or lessen your cancer risk. However, doctors have focused research on trying to find a solution to the problem.

Key Points: Sudden Onset Alcohol Intolerance

Important points about sudden onset alcohol intolerance to keep in mind include:

  • Alcohol intolerance may be confused with other conditions such as an allergy to alcohol, an allergy to drink ingredients or a drug’s interaction with alcohol
  • You are at higher risk for alcohol intolerance if you are of East Asian descent
  • Alcohol intolerance is a genetic condition and it is, therefore, likely that your family members are at risk
  • There is no treatment for alcohol intolerance at this time, other than avoiding alcohol
  • Mild alcohol intolerance can mean you have minimal symptoms, but if you do not avoid alcohol then you are at higher risk for having cancer

If you or a loved one struggle with alcohol and are trying to stop drinking, our trained, caring staff members at The Recovery Village are here to help you. Contact us today to learn more.


Australasian Society of Clinical Immunology and Allergy. “Alcohol Allergy.” March 2019. Accessed April 18, 2019.

Ushida Y, Talaylay P. “Sulforaphane accelerates acetaldehyde metabolism by inducing aldehyde dehydrogenases: relevance to ethanol intolerance.” October 2013. Accessed April 18, 2019.

National Institute on Alcohol Abuse and Alcoholism. “Alcohol “Flush” Signals Increased Cancer Risk Among East Asians.” March 23, 2009. Accessed April 18, 2019.