Green tea is made from the leaves from Camellia sinensis that have undergone minimal oxidation during processing. Green tea originated in China, but it has become associated with many cultures throughout Asia. Green tea has recently become relatively widespread in the Western World where black tea has been traditionally consumed.
Green tea has become the raw material for extracts used in various beverages, dietary supplements, and cosmetic items. Many varieties of green tea have been created in the countries where it is grown. These varieties can differ substantially due to variable growing conditions, horticulture, production processing, and harvesting time.
Many claims have been made for the beneficial health effects of green tea consumption, but they have generally not been borne out by scientific investigation; excessive consumption is associated with some harmful health effects but moderate, regular consumption is safe.