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Green Tea

Natural health supplements sometimes have unexpected side effects or interactions with medication that can lead to adverse reactions that are sometimes life threatening. The following is a list of cautions that you should be aware of before using Green Tea. These are referred to as drug/herb interactions.

Warning 1 - Antacids: May decrease the therapeutic effects of green tea.

Warning 2 - MAOIs: Drinking large amounts of green tea while using MAOIs can cause hypertensive crisis.

Warning 3 - Xanthines: Largen amounts of green tea increase the action of xanthines.

Warning 4 - Pregnancy Risks: Green tea contains caffeine, catechins and tannic acids. All three substances have been linked to pregnancy risks. Drinking a large amount may cause neural tube birth defect in babies. Moderate consumption should be okay but consider avoiding it altogether during early pregnancy to be on the safe side.

Warning 5 - Diabetes patients: Green tea contains caffeine, which can increase blood sugar levels. Diabetes patients should drink it cautiously.

Warning 6 - Anticoagulants: Green tea contains small amounts of vitamin K, which can make anticoagulant drugs, such as warfarin, less effective. Use caution when combining with ginkgo, ibuprofen, aspirin, and other NSAIDs.

Warning 7 - Liver disease: If you have severe liver disease the level of caffeine in the blood may build up and last longer. It is not known how or why green tea might cause liver damage.

Warning 8 - Athletes: The NCAA lists products containing green tea extract as IMPERMISSIBLE for athletes.

Warning 9 - Bronchodilators: Large amounts of green tea increase the action of some bronchodilators.

Green tea has nine muscle-relaxing compounds including L-Theanine, more benefits than just about any other plant.

Used as a natural health remedy: Green Tea is used internally for:
  • Dementia
  • Diet aid (See other herbs for weight loss)
  • Fighting cancer
  • Hair loss
  • Heart disease
  • Lower cholesterol
  • Menopause (See other herbs for menopause)
  • Prevent diabetes
  • Reducing fat - dieting
  • Reducing symptoms of menopause
  • Stroke

The FDA concludes that there is very limited credible evidence for qualified health claims specifically for green tea and breast cancer and for green tea and prostate cancer, provided that the qualified claims are appropriately worded so as to not mislead consumers.

In October 2006, the FDA approved an ointment based on green tea. New Drug Application number N021902, for Kunecatechins ointment 15% (proprietary name Veregen) was approved on October 31, 2006. Kunecatechins ointment is indicated for the topical treatment of external genital and perianal warts.

Side Effects of Green Tea

The minor side effects of taking Green Tea internally include:
  1. Abdominal bloating
  2. Abdominal pain
  3. Dizziness
  4. Frequent urination.
  5. Headache
  6. Heartburn
  7. Gas
  8. Insomnia
  9. Irritability
  10. Muscle pain
  11. Nausea
  12. Restlessness
  13. Stomach ache
  14. Vomiting
In rare cases green tea may provoke an adverse reaction that should be reported to your doctor. These may include, but are not limited to:
  • Anxiety or agitation
  • Heart palpitations
  • High blood pressure (hypertension)
  • Irregular heart rhythm (arrhythmia)
  • Rapid breathing or difficulty breathing
  • Rapid heart rate (tachycardia)
  • Seizures
Other side effects may also occur when using Green Tea. (See form below) There is also a possibility of an allergic reaction. The signs of an allergic reaction, including an unexplained rash, hives, itching, swelling of the mouth or throat, wheezing, or difficulty breathing or swallowing. If you suspect an allergic reaction get medical help as soon as possible.

As with any herb, a serious allergic reaction is possible. Seek immediate medical attention if you notice any symptoms of a serious allergic reaction. These may include a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Return to the Herb List.

For questions and answers about the side effects of herbs see the Herb Forum

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This consumer advocate website is protected by copyright 2011 Askdocweb, Inc. All Rights Reserved. This is a layman's report on Green Tea and is not intended to replace discussions with a health care provider. Do not use the information on this forum as a substitute for your doctor's advice. Always consult your doctor before taking any drug and follow your doctor's directions. Source material: Food and Drug Administration, Medline, Physician's Desk Reference, and the largest community of people in the world, those who are concerned about side effects and healthcare.
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