Oolong tea is a product made from the leaves, buds, and stems of the Camellia sinensis plant. This is the same plant that is also used to make black tea and green tea. Some people take oolong tea by mouth to sharpen thinking skills and improve alertness.
Some people take oolong tea by mouth to sharpen thinking skills and improve alertness. It is also taken by mouth for weight loss, to prevent cancer, to prevent brittle bones (osteoporosis), to boost the immune system, and to treat diabetes, heart disease, high cholesterol, and hardening of the arteries (atherosclerosis). But there is limited scientific evidence to support these uses.