"In the study, Bukowski and his co-authors isolated from ordinary black tea a substance called L-theanine." "Bukowski said L-theanine is broken down in the liver to ethylamine, a molecule that primes the response of an immune system element called the gamma-delta T cell." "We know from other studies that these gamma-delta T cells in the blood are the first line of defense against many types of bacteria, viral, fungal and parasitic infections," he said. "They even have some anti-tumor activity." The T cells prompt the secretion of interferon, a key part of the body's chemical defense against infection, Bukowski said. "We know from mouse studies that if you boost this part of the immune system it can protect against infection," he said. http://www.chronicfatiguesupport.com/library/showarticle.cfm/ID/4536/ This is actually an article from Prohealth.com but due to brain fog, I forget to look at it often. A customer from Bangladesh taught me a trick to mellow out Green teas tannic acid. It's the tannic acid that tears up our sensitive stomachs. Have a cup of hot water ready. Dip the tea bag in for ~5 seconds. (Tannic acid is very water soluable). Brew as usual.