Green tea is made from the plant called Camellia sinensis. The dried leaves and leaf buds of Camellia sinensis are used to produce various types of teas. Green tea is prepared by steaming and pan-frying these leaves and then drying them.

Green tea is taken by mouth to improve mental alertness and thinking.

It is also taken by mouth for depression, non-alcoholicfatty liver disease (NAFLD), inflammatory bowel disease (ulcerative colitis or Crohn’s disease), weight loss and to treat stomach disorders, vomiting, diarrhea, headaches, and bone loss (osteoporosis).

Green tea can cause stomach upset and constipation in some people. Green tea extracts have been reported to cause liver problems in rare cases.

Green tea is possibly unsafe when taken in long-term or in high-doses. Caffeine in the tea, a substance present also in coffee, may cause side effects. These side effects can range from mild to serious and include headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heart burn, dizziness, ringing in the ears, convulsions, and confusion.


If you are pregnant or breast-feeding take only small amounts of green tea—about 2 cups per day is POSSIBLY SAFE. This amount of green tea provides about 200 mg of caffeine. However, drinking more than 2 cups of it may be unsafe. High doses of green tea have been linked to theincreased risk of miscarriage and other negative effects due to the caffeine content. Green tea might also increase the risk of birth defects associated with folic acid deficiency. In women who are nursing, caffeine passes into breast milk and can affect a nursing infant. Don’t drink an excessive amount of green tea if you are pregnant or breast-feeding.



Caffeine in the tea may speed up the nervous system. Hence, it is not wise to combine it with other stimulant drugs like Amphetamines, Cocaine and Ephedrine. This combination of stimulant drugs might cause serious problems including increased heart rate and high blood pressure.

The following doses have been studied in scientific research:


For high cholesterol: Green tea or green tea extracts containing 150 to 2500 mg catechins, taken in single or 2 divided doses daily for up to 24 weeks, has been used.

For abnormal development of cells of the cervix (cervical dysplasia): 200 mg of green tea extract, taken by mouth daily along with a green tea ointment applied twice weekly for 8-12 weeks, has been used.

For high blood pressure: A green tea drink, made by boiling a 3 gram tea bag with 150 mL water, has been used three times daily about 2 hours after each meal for 4 weeks. Also, 379 mg of a specific product containing green tea extract (Olimp Labs, Debica, Poland), taken daily with the morning meal for 3 months, has been used.

For low blood pressure: 400 mL of green tea taken before lunch has been used.

For thick, white patches on the gums (oral leukoplakia): 3 grams of mixed green tea taken by mouth and applied to the skin for 6 months has been used.

For osteoporosis: Capsules containing 500 mg of green tea polyphenols, taken twice daily alone or while practicing tai chi for 60 minutes three times weekly for 24 weeks, has been used.


For genital warts: A specific green tea extract ointment (Veregen, Bradley Pharmaceuticals; Polyphenon E ointment 15%, MediGene AG) applied three times daily to warts for up to 16 weeks, has been used. This product is FDA-approved for treating this condition.

For abnormal development of cells of the cervix (cervical dysplasia): A green tea ointment has been used alone twice weekly, or in combination with 200 mg of green tea extract taken by mouth daily for 8-12 weeks.

For thick, white patches on the gums (oral leukoplakia): 3 grams of mixed green tea taken by mouth and applied to the skin for 6 months has been used.


Available brands:

  • Fit-N-Trim
  • Fitrum (Herbs & Nature)
  • Gloww (Mega Life sciences)
  • GNC Natural Brand Green Tea Extract

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