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Green Tea

What are other common names?

  • Camellia sinensis
  • Black Tea
  • Green Sencha Tea
  • Green Tea Extract
  • Green Tea Polyphenolic Fraction
  • GTP
  • GTPF
  • Japanese Tea
  • Kunecatechins
  • Oolong Tea
  • Poly E
  • Polyphenon E
  • PTV
  • Tea Extract
  • Tea Green
  • Veregen
  • Yame Green Tea
  • Yame Tea

What is this product used for?

Green tea is used by some people to increase alertness or improve mental performance. Others use it to lower cholesterol levels and prevent hardening of the arteries. Some people feel it protects the brain and lowers the chance of stroke. Green tea is used by some people with blood pressure problems or to help prevent cancer. Green tea may also help with genital warts or certain kinds of infection. Other people may use green tea to help with mouth problems or to lower uric acid levels in the blood.

What are the precautions when taking this product?

  • Always check with your doctor before you use a natural product. Some products may not mix well with other drugs or natural products.

  • This product interferes with MANY drugs. It reduces the effectiveness of many drugs. It increases side effects of some drugs. Talk with your doctor before you start using this product.

  • This product may interfere with some lab tests. Be sure to talk with your doctor about this and all drugs you are taking.

  • Be sure to tell your doctor that you take this product if you are scheduled for surgery or tests.

  • Limit caffeine (teas, coffee, colas) and chocolate intake.

  • Take extra care if you are taking drugs to thin your blood. These are drugs like warfarin (Coumadin), heparin, or enoxaparin (Lovenox).

  • Take extra care if you are taking drugs to dissolve blood clots. These are drugs like alteplase (Activase), reteplase (Retevase), or streptokinase.

  • Take extra care if you are taking drugs to help with swelling or inflammation. These are drugs like nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, ibuprofen (Advil), or naproxen (Naprosyn).

  • Take extra care and check with your doctor if you have:

    • Bleeding problems

    • Liver problems

    • Blood pressure problems

    • Diabetes

    • Cancer

  • Keep hard candies, glucose tablets, liquid glucose, or juice on hand for low blood sugar.

What should I watch for?

  • Upset stomach

  • Feeling dizzy

  • Heartburn or belly pain

  • Increased gas

  • Restlessness

  • Sleeping problems

  • Feeling anxious

  • Dry mouth

When do I need to call the doctor?

  • Signs of a very bad reaction. These include wheezing; tightness in the chest; fever; itching; bad cough; blue skin color; seizures; swelling of face, lips, tongue, or throat. Go to the ER right away.

  • Signs of low blood sugar. These include hunger, dizziness, shaking, a fast heartbeat, confusion, or sweating.

  • Signs of liver problems. These include upset stomach or throwing up, belly pain, feeling tired, dark urine, yellow skin or eyes, not hungry.

  • Very bad throwing up

  • Very bad loose stools

  • Very bad headache

  • Bruising or bleeding that is not normal

  • Changes in your menstrual periods like lots of bleeding, spotting, or bleeding between cycles

Where can I learn more?

National Center for Complementary and Alternative Medicine

Last Reviewed Date


Consumer Information Use and Disclaimer

This information is not specific medical advice and does not replace information you receive from your healthcare provider. Only your healthcare provider has the knowledge and training to provide advice that is right for you. You should not rely on this information in deciding whether or not to use, or accept your healthcare provider’s advice regarding use of, any natural products or similar treatments, therapies, or life-style choices. This information does not endorse any natural products or similar treatments, therapies, or life-style choices as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information. It does NOT include all information about natural products, possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to you. You must talk with your healthcare provider for complete information about your health and treatment options.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.