Green tea is a "true" tea, meaning it is made solely with the green tea leaves (Camellia sinensis), that have undergone minimal oxidation during processing. Green tea originates from China and has become associated with many cultures in Asia from Japan to the Middle East. Drinking green tea and herbal green tea is reputed to be helpful in treating cancer, high cholesterol levels, rheumatoid arthritis, cardiovascular disease, impaired immune function and infection . Other traditional uses of herbal green tea include treating flatulence (gas), regulating body temperature and blood sugar, promoting digestion and improving mental processes. It has been extensively studied in people, animals and laboratory experiments.