Is Green Tea Safe During Cancer Treatment?

Most people with cancer can drink moderate amounts of brewed green tea safely, and many find it a low‑calorie, pleasant beverage. Evidence on green tea preventing or treating cancer is mixed, so it shouldn’t be used as a therapy, but ordinary tea drinking is generally considered safe. ^{[1] [2]}

What the evidence shows

• Green tea contains polyphenols (like catechins/EGCG) with antioxidant activity, but large population studies and reviews show inconsistent links between green tea and cancer prevention. ^{[1] [2]}
• As a daily beverage, green tea is a healthy, low‑calorie choice; however, drinking very hot tea can raise the risk of esophageal (food pipe) injury and possibly cancer, so let hot drinks cool before sipping. ^[1]

Safety during treatment

• Brewed tea vs supplements: Brewed green tea at customary amounts is generally safe, but high‑dose green tea extracts or concentrated capsules can be riskier and may interact with medicines; stick to tea rather than pills unless your oncology team advises otherwise. ^[1]
• Drug interactions: Many cancer treatments can be affected by herbs and supplements; oncology teams routinely recommend reporting all herbal products because they may change how chemotherapy or targeted drugs work. ^[3]
• Timing and moderation: If you’re undergoing chemo, immunotherapy, or targeted therapy, it’s prudent to limit to 1–3 cups per day, avoid supplements, and discuss any concerns with your care team, especially if you have liver issues or are on drugs with narrow therapeutic windows. ^[3]

Practical tips for safe tea drinking

• Let hot tea cool to warm before drinking to avoid esophageal irritation. ^[1]
• Choose brewed green tea over concentrated extract supplements unless specifically approved. ^[1]
• Keep total caffeine intake modest if you have sleep problems, palpitations, or reflux; green tea has less caffeine than coffee but can still affect sensitive individuals. ^[1]
• During treatment, always tell your oncology team about any teas, herbs, or supplements, since they may recommend temporary adjustments around infusion days. ^[3]

Bottom line

• Yes, brewed green tea is generally safe for most people with cancer when consumed in moderation and not scalding hot. ^[1]
• It does not have proven cancer‑preventive or curative effects, and high‑dose supplements should be avoided unless your clinician approves. ^[1]
• Always keep your care team informed about all beverages and supplements so they can check for drug interactions. ^[3]