Four cups of tea or coffee a day could be good for the liver, according to new research.
A study found that increased caffeine intake may reduce fatty liver in those with non-alcohol fatty liver disease (NAFLD).
Seven out of 10 people diagnosed with diabetes or who suffer from obesity have the condition, and cases are rising.
There are no effective treatments for NAFLD except diet and exercise, reports journal Hepatology.
Professor Paul Yen, of America's Duke University, carried out a study using cell cultures and mice models.
He found that caffeine stimulates the metabolization of lipids stored in liver cells and decreased the fatty liver of mice that were fed a high-fat diet.
The findings suggest that consuming the equivalent caffeine intake of four cups of coffee or tea a day may be beneficial in preventing and protecting against the progression of NAFLD in humans.
Prof Yen said: "This is the first detailed study of the mechanism for caffeine action on lipids in liver and the results are very interesting.
"Coffee and tea are so commonly consumed and the notion that they may be therapeutic, especially since they have a reputation for being "bad" for health, is especially enlightening."
The discovery could lead to the development of caffeine-like drugs that do not have the usual side effects related to caffeine, but retain its therapeutic effects on the liver.