Another anti-oxidant, green leaf tea has become one of the world's most popular beverages. True tea comes from only one plant, Camellia sinensis, and is naturally processed to various degrees to produce black, green, or oolong tea (a black and green tea blend). Herbal teas are not true teas as they are not made from the Camellia sinensis plant, and therefore do not have the antioxidants that come from this plant. A growing body of scientific evidence suggests that the antioxidants in tea, called flavonoids, help neutralize "free radicals" in the body, therefore, helping to maintain healthy cells and tissues.

Tea is seen by many as more than just a beverage; it is also noted for its restorative effects. Emerging evidence suggests that this folklore actually may have a scientific basis, though more work is needed. Scientific research is just beginning to systematically explore the possibility that tea can restore the body and mind or help maintain homeostasis or balance. Researchers are investigating the relaxation and rejuvenation properties of tea, which are unrelated to the effects of caffeine, as well as tea's potential to stimulate alertness and mental performance.

While tea can have a mildly diuretic effect, much of the fluid it provides is retained by the body. In addition, tea contains other minerals, such as potassium, that help maintain a body's fluid levels, so tea's diuretic effect does not pose a huge concern. (Diuretics generally deplete the body of potassium.) Both black and green tea may help prevent or delay the formation of tumors specifically in the skin, lungs, esophagus, stomach and colon. Black tea consumption is associated with a reduced risk of heart disease and stroke. Drinking more than four cups of tea per day was associated with a 69 percent reduced risk of stroke compared to those who drank less tea each day. Studies indicate that tea may help reduce the risk of heart disease and stroke in two ways: by improving the health of the body's circulatory system of arteries and veins; and by reducing the risk of a blood clot.