As high doses of green tea extract supplements for weight loss become more popular, potential liver toxicity becomes a concern.

In the last decade, dozens of people have been diagnosed with the condition.

However, drinking green tea in the weeks before taking supplements likely reduces risk, according to researchers in Penn State’s College of Agricultural Sciences.

Researchers gave mice high doses of the green tea polyphenol epigallocatechin-3-gallate (EGCG). The dosage was equivalent to the amount of the polyphenol found in some dietary supplements taken by humans.

One group of mice was pretreated with a diet containing a low level of ECGC for two weeks prior to receiving high doses of the polyphenol.

Another group was fed a diet that did not include EGCG prior to receiving the high, supplement-like doses.

After three days of high doses, the scientists tested the blood of the mice to determine how their livers handled the EGCG. Pretreated mice had a 75 percent reduction in liver toxicity compared to untreated mice.