Does Coffee Cause Cancer?

In 1991, IARC put coffee drinking in Group 2B. That label means "possibly carcinogenic to humans." Carcinogenic just means cancer-causing. IARC is the World Health Organization's cancer agency. Bladder cancer was the main worry at the time.

The label stuck in the public mind for 25 years. It is now gone. What replaced it is more useful than a plain yes or no.

IARC gathered 23 scientists to look again. They reviewed coffee, mate, and very hot drinks. The group read more than 1,000 studies in people and animals. The results came out in June 2016. They became Volume 116 of the IARC Monographs.

For coffee, the group found the evidence too weak to judge. Coffee moved to Group 3. That label reads "not classifiable as to its carcinogenicity to humans."

The review said more than that. Many studies showed no cancer-causing effect from coffee for three cancers:

• Pancreatic cancer.
• Breast cancer.
• Prostate cancer.

The group also found lower risk in coffee drinkers for two cancers. One is liver cancer. The other is cancer of the uterine lining, called the endometrium. For more than 20 other cancers, the evidence was not clear either way.

This point gets lost often. Group 3 means the evidence is too weak to sort a substance either way. It describes the state of the science. It is not a safety certificate.

For coffee, the wider picture is still reassuring. The reason is size. A verdict of "we cannot say" built on 1,000 studies is not the same as one built on three.

The same group flagged something else. This is the part worth acting on. Drinking very hot drinks went into Group 2A, "probably carcinogenic to humans." The cancer behind that label is cancer of the esophagus. The esophagus is the tube that carries food from the throat to the stomach.

IARC defined "very hot" with a number. It means any drink taken above 65 degrees Celsius. That is 149 degrees Fahrenheit.

The evidence came from places where drinks are served near 70 degrees Celsius. IARC named China, Iran, Turkey, and parts of South America. In those studies, esophageal cancer rates rose as the drinking heat rose. Animal work added limited evidence that very hot water alone can cause cancer.

Christopher Wild led IARC then. He put it plainly. It appears to be the heat, rather than the drinks themselves, that is responsible. Cold mate was tested on its own. It went into Group 3, next to coffee.

IARC gave the global picture. Then it declined to guess a share. Esophageal cancer was the eighth most common cause of cancer worldwide. About 400,000 deaths were recorded in 2012. That is roughly 5% of all cancer deaths. How many of those cases trace to very hot drinks is not known.

NCI's own prevention review is a useful check on scale. For esophageal squamous cell carcinoma, it lists two factors with adequate evidence of raised risk. Those are cigarette smoking and drinking alcohol. Together they may explain roughly 90% of such cases in Western countries like the United States. Very hot drinks do not appear on that NCI list at all. Our page on esophageal cancer covers the two main types and how they differ.

Roasting coffee creates acrylamide. This chemical forms when some foods are heated to high heat. NCI lists coffee among the major food sources. The rest of that list includes French fries, potato chips, crackers, bread, cookies, breakfast cereals, canned black olives, and prune juice.

The evidence has a familiar shape. In rodents, acrylamide raises the risk of several cancers. The body turns it into glycidamide, which damages DNA. The National Toxicology Program lists acrylamide as reasonably anticipated to be a human carcinogen. That listing rests on the animal studies.

Human studies read differently. NCI reports that a large number of them, both case-control and cohort, found no steady link between acrylamide in food and any cancer. People and rodents take in acrylamide at different rates. They also break it down differently.

One number puts food in perspective. People who smoke carry three to five times more acrylamide markers in their blood than people who do not. Our page on high-temperature frying covers how cooking method changes those levels.

IARC is careful here, and its 2016 release said so. The Monographs sort cancer hazards. A hazard is the potential to cause cancer. The label does not say how much risk comes with real-world use. IARC offered its own example. Smoking is Group 1, carcinogenic to humans. That label says nothing about the risk per cigarette.

Applied here: a Group 2A label on very hot drinks does not put a hot latte next to a cigarette.

Coffee is not classified as a cause of cancer. The review behind that verdict is one of the largest ever done on a single drink. The part to act on is heat. Letting a hot drink cool for a few minutes covers the only finding in the 2016 review that pointed to real harm. For other food and drink claims, see our look at artificial sweeteners.

• International Agency for Research on Cancer, IARC Monographs evaluate drinking coffee, mate, and very hot beverages, Press Release 244, June 15, 2016, accessed August 6, 2026
• National Cancer Institute, Acrylamide and Cancer Risk, accessed August 6, 2026
• National Cancer Institute, Esophageal Cancer Prevention (PDQ) - Health Professional Version, updated April 10, 2025, accessed August 6, 2026