Research

Mixed

High-dose concentrated green tea extracts, particularly those rich in EGCG, can cause liver toxicity, whereas moderate consumption of brewed green tea is generally safe.

Enjoying brewed green tea is generally safe and healthy. However, be cautious with green tea extract supplements, especially those high in EGCG. These concentrated forms have been linked to liver damage in some cases, particularly when taken on an empty stomach or in high doses. Consult a healthcare provider before using these supplements.

GoodQualifiesHIGH confidence
Green tea consumption has a long history of safe use whereas the isolated, purified, and concentrated catechin components of green tea appear to have adverse effects and currently are not considered safe for food ingredient use... hepatic and intestinal toxicities associated with the consumption of high doses of GTC preparations were reported in animal studies... recent reviews of published case reports suggests a possible causal relationship between concentrated green tea extracts, particularly EGCG, and liver damage.
Ali H. Abdelrahman et al. · Toxicological Sciences · 2011

Why this rating

Based on animal studies, human case reports, and mechanistic studies cited in the review.

Source

The Safety and Regulation of Natural Products Used as Foods and Food Ingredients

Ali H. Abdelrahman et al. · Toxicological Sciences · 2011

DOI 10.1093/toxsci/kfr198

narrative_reviewCited 168×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →