In ordinary language, tea is often used to mean any beverage produced from the leaf of any plant. Technically, tea comes from the leaf of one particular plant. Tea is more widely consumed than any beverage in the world other than water.
Most tea consumed is black tea, which is produced by a process which oxidizes the green leaf.
GTP has been widely studied in recent years and appears to be an important substance for the chemoprevention of cancer. On the Role of Tea in Modifying Causes of Major Human Cancers 2. Effects of Green Tea and Its Components on Lung Tumorigenesis Induced by a Tobacco-Specific Nitrosamine 3. Protection against Cancer Risk by Japanese Green Tea Tea Polyphenols as Antioxidants 5. Inhibition of in Vitro Neoplastic Transformation by Tea Ingredients 6.