Green tea contains highly antioxidant polyphenolic compounds and may potential have preventive effects against cancer. Tea extracts have become a field of interest, due to their notional antibacterial activity. The preservation of processed organic food and the treatment of persistent bacterial infections are particularly being investigated. Green tea leaves and extracts have shown to be effective against bacteria responsible for bad breath and recent research has shown that plant-derived polyphenolic compounds are promising nutraceuticals for control of various disorders such as cardiovascular, neurological, and neoplastic disease.

The leaves have been used in traditional Chinese medicine and other medical systems to treat asthma (functioning as a bronchodilator), angina pectoris, peripheral vascular disease, and coronary artery disease. Additional traditional benefits of green tea include improved urine flow, relief of joint pain, and improved resistance to diseases.

Green tea’s biggest benefit? "It's all about the catechin content," says Beth Reardon, RD, a Boston nutritionist. Catechins are antioxidants that fight and may even prevent cell damage. Green tea is not processed much before it's poured in your cup, so it's rich in catechins. Research Shows Green tea improves blood flow and lowers cholesterol. A 2013 review of many studies found green tea helped prevent a range of heart-related issues, from high blood pressure to congestive heart failure.