Green tea has been proven to provide health benefits, but taking it in high doses especially in supplement form might cause even more problem.

A middle-aged man from Dallas, Texas was admitted to the hospital and in need of liver transplant. His doctors suspect that over-the-counter green tea supplements, which he has been taking for three months, was the cause of his liver injury.

"It was shocking because I'd only heard about the benefits," the patient, named Jim McCants, told the BBC. "I'd not heard about any problems."

Dangers Of Green Tea Extracts

McCants started taking green tea extract in supplement form in order to aid in his drive to become healthier. He started eating healthier and regularly exercising, but the promise of antioxidant benefits from the supplements drew him in.

However, one day, his wife noticed that his face has turned yellow. He was advised by his hepatologist to immediately have a liver transplant within a week after he had been admitted to the hospital.

Like any other type of food, green tea, when consumed in excessive amounts, can cause serious problems. A previous study by the U.S. National Institute of Health confirmed that a large intake of green tea, when taken as a drink or from a supplement, is linked to acute liver failure.

Another investigation by the European Food Safety Authority identified catechins from green tea, while generally safe, poses serious health concerns when taken in large doses or above 800 mg a day.

Is Green Tea Safe?

The danger, however, only exists to those who are taking green tea extract supplements. People who drink green tea daily should not worry about damaging their livers because three to five cups a day only has at least 250 mg of catechins.

"If you are drinking modest amounts of green tea you're very safe," assured Herbert Bonkovsky, the director of liver services at Wake Forest University School of Medicine. "The greater risk comes in people who are taking these more concentrated extracts."

Benefits of drinking green tea regularly include intake of antioxidants which can ward off free radicals and lower the risk of cancer. It also aids in weight loss.