# Safety & Interactions
EGCG is the main catechin in **green tea**, and although it is generally well tolerated, concentrated EGCG extracts raise real safety and interaction questions in oncology.
### General tolerability
At commonly used doses, EGCG is usually well tolerated. The most common side effects are mild gastrointestinal symptoms such as nausea, abdominal discomfort, and loose stools.
### Major safety issues
#### Liver risk at higher doses
Rare hepatotoxicity has been reported, especially with concentrated extracts at doses above roughly **800–1,000 mg/day** and particularly when taken on an empty stomach.
#### Bleeding and platelet effects
EGCG has mild antiplatelet activity, so extra caution may be needed in people with thrombocytopenia, bleeding risk, or anticoagulant use.
#### Iron and folate considerations
* EGCG can reduce iron absorption
* It may interact with folate-related pathways through dihydrofolate reductase-related biology
* Iron and folate timing may need review in susceptible patients
### Major drug interaction caution: bortezomib
This is the clearest high-priority interaction in the EGCG literature.
**Avoid combining EGCG with bortezomib (Velcade).** EGCG has been shown to antagonise bortezomib's proteasome-inhibition mechanism, which may reduce treatment efficacy.
### Other interaction considerations
* CYP3A4-related drug metabolism
* P-glycoprotein modulation
* possible effects on taxanes, irinotecan, and other oncology drugs
* timing issues around chemotherapy and radiotherapy
### Practical takeaway
EGCG is not a high-toxicity compound in routine use, but high-dose extracts are not casual supplements. The main concerns are liver safety, drug interactions, and timing in active treatment.
### Key References
Epigallocatechin-3-Gallate Therapeutic Potential in Cancer: Mechanism of Action and Clinical Implications\
Anticancer Molecular Mechanisms of Epigallocatechin-3-Gallate (EGCG)\
The roles of epigallocatechin gallate in the tumour microenvironment, metabolic reprogramming, and anti-cancer therapy\
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This information is for education only. It is not medical advice, diagnosis, or treatment. Please speak with a qualified clinician before making changes to care, medication, or supplement use.
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