Description: Very high doses of caffeine and acetaminophen (such as Tylenol), taken together, could lead to liver damage, researchers warn.

This combo produces a byproduct enzyme that's toxic to the organ, researchers from the University of Washington report.

This toxic twosome can occur not only by drinking caffeine while taking acetaminophen, the experts added, but also from large doses of painkillers that combine caffeine and acetaminophen. These painkillers are often used to treat migraines, menstrual discomfort and other conditions.

"Caffeine can interact with an enzyme that can form a toxic metabolite of acetaminophen in such a way that it increases the formation of that toxic metabolite," said lead researcher Sid Nelson, a professor of medicinal chemistry. "This can result in liver damage," he said.

In the study, Nelson's team tested the effects of acetaminophen and caffeine on E. coli bacteria. These bacteria had been genetically engineere