Green tea is a very lowly oxidized type of tea, unlike oolong and black teas which go through an oxidation process. Leaves of Camellia sinensis var. Sinensis are better suited for producing green tea than those from Camellia sinensis var. Assamica which are usually used to make black tea. Originating in China, production spread out into other areas of Eastern Asia. There are many styles of green tea that differ substantially in flavor, leaf look, and production process. Green tea is a type of tea with the highest antioxidant properties. There are many research studies on its health effects, but there is little evidence showing any effects on people's health.