How Does Alcohol Cause Cancer? New U.S. Surgeon General Advisory Explained

Many are wondering how alcohol causes cancer after the U.S. Surgeon General Vivek Murthy released an advisory on Friday, January 3, that calls for new cancer risk warning labels for alcoholic drinks. According to a 2019 survey attached to the new report, only 45% of Americans are aware that alcohol consumption increases cancer risk. This is despite the report finding that alcohol is responsible for 100,000 cancer cases and 20,000 cancer deaths in the U.S. every year.

How does alcohol consumption increase cancer risk?

Alcohol increases cancer risk in four key ways, according to the new 2025 U.S. Surgeon General advisory.

1. Acetaldehyde formation – The ethanol in alcohol is broken down in the liver into acetaldehyde, which is a known carcinogen. This chemical damages DNA in several ways and interrupts DNA replication, increasing the risk for cancer.
2. Oxidative stress – The body naturally generates reactive oxygen species (or ROS) that can damage fats, proteins, and DNA. As noted in an NIH study, alcohol “promotes the generation of ROS” and also reduces the level of antioxidants that help clear ROS.
3. Hormone changes – Alcohol alters the levels of multiple hormones, including estrogen, oestrogen, and insulin, per Cancer Research UK. This leads to cells dividing more often than usual, increasing cancer risk, while higher estrogen levels can negatively impact breast tissue.
4. Greater absorption of carcinogens – Other carcinogens, such as chemicals from tobacco smoke, can dissolve in alcohol. These additional carcinogens increase the risk for mouth and throat cancers.

Having two drinks a week, the advisory says, increases the risk for women developing cancer from 16.5% to 21.8%, while the risk for men developing cancer jumps from 10% to 13.1%.

Given the casual link between alcohol and cancer, the US Surgeon General calls for new health warning labels on alcohol beverage containers. It cites that 47 countries “require alcohol warning labels related to health and safety,” including South Korea and more recently Ireland, which will have these new labels in 2026.