Alcohol Intolerance: Symptoms, Tests & Alcohol Allergy

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Alcohol intolerance is a rare condition that causes people to experience unpleasant symptoms when drinking alcohol. It is not normally dangerous; however, its symptoms are unpleasant enough that most people who have it will avoid heavy amounts of alcohol.

What Is Alcohol Intolerance?

Alcohol intolerance is a condition in which your body cannot break down alcohol normally. This results in a buildup of a chemical called acetaldehyde, which is toxic. This condition can cause many symptoms, but a stuffy nose and flushing in the face are the most common. Other symptoms of alcohol intolerance can include:

  • Flushing of the neck and chest
  • Nausea and vomiting
  • Headache
  • Diarrhea
  • Rapid heartbeat
  • Low blood pressure
  • Shortness of breath
  • Hives
  • Swelling of the tongue or throat

In those without alcohol intolerance, alcohol is broken down  into a chemical called acetaldehyde, which is immediately broken down into another chemical called acetate. 

People with alcohol intolerance have a mutation in the enzyme that breaks acetaldehyde down into acetate, causing the acetaldehyde to build up in the body. Over the long term, acetaldehyde can increase the risk of cancer. On a short-term basis, it will only cause the unpleasant symptoms that alcohol intolerance is known for.

Alcohol Allergy vs. Intolerance

Alcohol intolerance is different from an alcohol allergy. Alcohol intolerance happens because a defective enzyme causes acetaldehyde to build up. Alcohol allergy occurs when the body’s immune system overreacts to alcohol. A true alcohol allergy is extraordinarily rare; an alcohol allergy is more often actually due to an allergy to another component of an alcoholic drink, such as an ingredient in a mixer, and this is mistaken for an alcohol allergy. Alcohol allergies and intolerance are different, but either one will still cause unpleasant symptoms when drinking alcohol.

What Causes Alcohol Intolerance?

Natural alcohol intolerance is caused by an abnormality in an enzyme called aldehyde dehydrogenase. This abnormality is most commonly caused by genetics, meaning that people with alcohol intolerance inherited the trait from at least one of their parents. Alcohol intolerance is most common in people of Asian descent.

While alcohol intolerance is normally caused by genetics, several other factors can also cause it. Some cancers have been found to suddenly cause alcohol intolerance, likely due to an effect on how acetaldehyde is processed.

Medications can also cause alcohol intolerance. The antibiotic metronidazole temporarily affects how the enzyme aldehyde dehydrogenase works, causing alcohol intolerance. Disulfiram is another medication that causes alcohol intolerance, but it is taken to cause alcohol intolerance deliberately. The purpose of this medication is to discourage drinking in those who find it difficult to stop. By creating an alcohol intolerance, the appeal of alcohol is greatly reduced. Disulfiram can be used as part of alcohol addiction treatment.

Can You Develop Alcohol Intolerance Over Time?

It would be very uncommon to develop a true alcohol intolerance over time. Most people with alcohol intolerance have it their whole lives or suddenly develop it in response to a medical change. There are negative effects of alcohol, like inflammation in the stomach, that can accumulate over time and become more sensitive to alcohol. These effects, however, are not true alcohol intolerances. 

Can You Develop a Sudden Alcohol Intolerance?

You can develop a sudden alcohol intolerance. Some medications, most notably disulfiram, inhibit the enzyme aldehyde dehydrogenase, causing a sudden onset of alcohol intolerance. Additionally, certain medical conditions can affect this enzyme and cause alcohol intolerance to develop suddenly.

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Alcohol Intolerance Symptoms

Alcohol intolerance symptoms are caused by the buildup of acetaldehyde that occurs as alcohol is metabolized. Symptoms of alcohol intolerance can include:

  • Facial redness
  • Worsening of existing asthma
  • Runny or stuffy nose
  • Diarrhea
  • Nausea or vomiting
  • Low blood pressure
  • Headache
  • Hangover symptoms
  • Heart palpitations
  • Low blood pressure 

Alcohol Flushing

Alcohol intolerance is sometimes called “Asian Flush” because it primarily affects those of Asian descent, and the main symptom is flushing in the face. The buildup of acetaldehyde causes this sudden redness. Facial flushing after drinking alcohol is typically the strongest indicator that alcohol intolerance may be present.

Diagnosing Alcohol Intolerance

Alcohol intolerance is normally diagnosed based on the symptoms experienced.  

Allergy Testing

Because an actual alcohol intolerance is quite rare, many people who believe they have an alcohol intolerance actually have an alcohol allergy. Allergy testing is often done to rule out an alcohol allergy before a diagnosis of alcohol intolerance is made. 

Genetic Testing

While there are no specific tests for alcohol intolerance, genetic testing can indicate whether you have the genetics associated with alcohol intolerance. As genetic testing becomes more advanced, testing the gene that influences alcohol dehydrogenase. This can reveal mutations in this gene and show if the body isn’t producing enough alcohol dehydrogenase.

Typically these two approaches are combined to help determine if alcohol intolerance is present. 

Alcohol Intolerance Treatment

Unless it is caused by a medication or a treatable medical condition, there is no cure for alcohol intolerance. Alcohol intolerance will be present for life, and there is no way to get rid of it. Someone with alcohol intolerance may be able to take medications that mask the symptoms, but these medicines will not deal with the underlying issue.

Avoidance of Alcohol

Because of the negative effects that alcohol causes in those with alcohol intolerance, avoiding alcohol is typically the best option. The unpleasant effects associated with alcohol often make this relatively easy. Avoiding alcohol may not be limited just to avoiding alcoholic beverages. Alcohol in hand sanitizer absorbed through the skin or alcohol in cough medicine can also cause alcohol intolerance symptoms. Avoiding anything with alcohol is ultimately necessary to prevent these symptoms. 


Some medications can help reduce the effects of alcohol intolerance; however, they only mask the symptoms. Antihistamines are the main medication used. The medicines, however, do not actually reduce acetaldehyde building up in your system. Because acetaldehyde can increase your risk of cancer, it is more advisable to avoid alcohol altogether than to mask the symptoms by using medications.

Alternative Drinks

Unfortunately, drinking alcohol is often a social activity, making it inconvenient not to drink in some situations. In these scenarios, you can drink alternative beverages like a non-alcoholic beer, sparkling grape juice or even something distinct from alcohol like soda. Alternative beverages offer the opportunity to engage in the social aspects of drinking without actually drinking.

Living With Alcohol Intolerance

Someone who does not use alcohol won’t usually know that they have an alcohol intolerance until they try to drink; this condition is only ever an issue when alcohol is used. For those who do enjoy alcohol, however, it can be more difficult. There is normally no way to get rid of alcohol intolerance. 

One important consideration for those with alcohol intolerance is exposure to alcohol in unexpected places. For example, drinking cough syrup that has alcohol can cause a reaction in someone who has alcohol intolerance. Alcohol intolerance requires mindfulness about potential exposures to alcohol.

Coping With Social Pressure

One difficult aspect of alcohol intolerance is that there can be social pressure to drink. It can be difficult for others to understand the concept of alcohol intolerance, and they may try to get you to drink despite the unpleasant effects it could cause you.

There are several potential strategies for coping with social pressure:

  • Avoid awkward situations: By avoiding situations where you are likely to experience social pressure, you can prevent this.
  • Be frank about your intolerance: If you are open about your decreased ability to use and enjoy alcohol, most people will be accepting.
  • Have a wingman: Having one other person present who understands your situation can help you not to be alone, significantly reducing the pressure of social situations.

Alcohol Intolerance and Misuse

Someone with alcohol intolerance may still be able to develop an addiction to alcohol if they push through the unpleasant symptoms. This can be dangerous, as prolonged exposure to high acetaldehyde levels can increase the risks of several types of cancers.
If you or someone you love is struggling with alcohol use, The Recovery Village at Cherry Hill can help you achieve lasting sobriety. Contact a Recovery Advocate today to learn more about alcoholism treatment programs that can support you in living a healthier, alcohol-free life.


Mayo Foundation for Medical Education and Research. “Alcohol intolerance.” April 6, 2023. Accessed June 7, 2023.

National Center for Advancing Translational Sciences. “Acute alcohol sensitivity.” Accessed June 7, 2023.

Delaware Health and Social Services. “Acetaldehyde.” January 2015. Accessed June 7, 2023.

Australasian Society of Clinical Immunology and Allergy. “Alcohol Allergy.” March 2019. Accessed June 7, 2023.

Morozova, Tatiana V.; Mackay, Trudy F.C.; Anholt, Robert R.H. “Genetics and genomics of alcohol sensitivity.” Molecular Genetics and Genomics, 2014. Accessed June 7, 2023.

Igumnova, Anastasia. “Alcohol Flush Reaction: Do You Have Alcohol Intolerance?” Atlas Blog. Accessed June 7, 2023.

Brooks, Philip J.; Enoch, Mary-Anne; et al. “The Alcohol Flushing Response: An Unreco[…] Alcohol Consumption.” PLoS Medicine, March 2009. Accessed June 7, 2023.

Bryant, Andrew J.; Newman, John H. “Alcohol intolerance associated with Hodgkin lymphoma.” CAMJ, May 14, 2013. Accessed June 7, 2023.

Wüthrich, B. “Allergic and intolerance reactions to wine.” Allergologie Select, September 2018. Accessed June 7, 2023.


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