For more details on this topic, see deuterium. A deuterium atom contains one proton, one neutron, and one electron. 2H (atomic mass 2.013553212724(78) u), the other stable hydrogen isotope, is known as deuterium and contains one proton and one neutron in its nucleus.
The caffeine in green tea, especially when taken in large amounts, can worsen diarrhea. Irritable bowel syndrome (IBS) : Green tea contains caffeine. The caffeine in green tea, especially when taken in large amounts, can worsen diarrhea and might worsen symptoms of IBS.
Drinking green tea only after eating may help reduce the symptoms of an upset stomach because the increased acid production is buffered by the food. Consuming decaffeinated green tea can also help if caffeine is the problem, while drinking tea without dairy products may help if you are lactose-intolerant.