What are the side effects of green tea?

What are the possible side effects of green tea ()? Although rare, allergic reactions to green tea may occur. Stop taking green tea and seek emergency medical attention if you experience symptoms of a serious allergic reaction including difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives.Heavy and prolonged consumption of green tea may be associated with esophageal cancer.Other less serious side effects have also been reported with the use of green tea. Talk to your doctor or health care provider if you experience
  • heartburn;
  • upset stomach;
  • loss of appetite;
  • constipation or diarrhea;
  • nervousness, irritability, or anxiety;
  • sleeplessness;
  • irregular heartbeats; or
  • headache.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.