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The information on this page was reviewed and approved by
Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was updated on September 21, 2021.

Alcohol and cancer risk

More than half of U.S. adults drink alcohol, according to the U.S. Centers for Disease Control and Prevention, but it’s not without risk. Alcohol use, especially in large quantities and in addition to smoking, heightens the risk for cancer.

Below, find details on the connection between alcohol and cancer.

Which products contain alcohol?

Alcohol, also known as ethanol or ethyl alcohol, is a chemical found in drinks like beer, wine and liquors, including whiskey, gin, rum, vodka, tequila, sake, brandy and some ciders. Alcohol may also be found in items you wouldn’t buy at a bar or restaurant, such as mouthwash, cough syrup, flavor extracts (like vanilla), hand sanitizer and perfume. When it comes to cancer, the risks are mainly connected with drinking alcoholic beverages.

Not all alcoholic drinks are created equal, though.

  • Public health experts classify one serving of alcohol as 0.6 ounces of pure alcohol, which varies across types of alcohol and tends to line up with the standard servings at a restaurant or bar.
  • One 0.6-ounce serving is typically found in 1.5 ounces of hard liquor (one “shot”), a 12-ounce can of beer, 5 ounces of wine, or 8 to 9 ounces of malt liquor.

Does alcohol cause cancer?

Many people wonder whether the food and beverages they consume may lead to cancer. In the case of alcohol, the connection is clear: Since 2000, the National Toxicology Program has named alcohol as a known human carcinogen—a substance that reliable research has shown causes cancer.

Alcohol is related to cancer in the:

Drinking heavily also seems to be a risk factor for stomach cancer. For other cancers, current evidence doesn’t point to a connection with alcohol, or the evidence so far is mixed. Research is ongoing, but the evidence for a link between alcohol and certain skin, prostate and pancreatic cancers is starting to emerge.

How are alcohol and cancer connected?

So, how exactly does alcohol cause cancer? There are a few potential ways that it could happen. Generally, alcohol is thought to damage the cells in various parts of the body, particularly the cells it comes in contact with the most, in areas such as the mouth and throat. This damage leads to DNA changes, increasing the risk of a cancer-causing mutation.

Researchers also think alcohol damages the DNA of a cell itself. One theory is that alcohol does this when it turns into a toxic chemical called acetaldehyde as it breaks down in the body. Or, that alcohol may trigger the production of more oxygen-containing molecules in the body, which puts stress on cells.

Alcohol may also make it harder for the body to process and use certain vitamins and nutrients that may help prevent cancer.

Research suggests that alcohol may increase the amount of estrogen in the body, increasing the risk of breast cancer.

How much alcohol is safe to drink?

For most types of cancer, research shows that the more alcohol a person drinks, the greater the risk. Dietary Guidelines for Americans 2020-2025, from the U.S. Department of Agriculture and the U.S. Department of Health and Human Services, says “adults of legal drinking age can choose not to drink or to drink in moderation.” According to their standards, that means:

  • No more than one serving per day for adult women
  • No more than two servings per day for adult men

For reasons other than cancer risk, the agencies recommend that some avoid alcohol altogether, including pregnant women, people younger than 21 and those with certain medical conditions.

Using tobacco in combination with alcohol is shown to be particularly risky, too. In fact, while both smoking and drinking are known to cause cancer on their own, the risk of combining the two activities does more than just add the two risk factors together—alcohol may help tobacco’s harmful chemicals enter the cells, increasing the risk of cancer.

It’s unclear based on research whether alcohol increases the risk of recurrence in those who’ve already had cancer. Anyone undergoing cancer treatment should ask their care team whether it’s safe to drink alcohol in any amount.