Any "tea" mixture that doesn't actually contain Camellia sinesis leaves is considered an herbal tea, which is also known as a tisane. Surprisingly, two international herbs, rooibos and yerba mate, are two of the most popular herbal infusions around. Besides the foriegn fixes, dried fruit is also used to create cups of "tea", not to mention flowers like chamomile and jasmine. Though these concoctions have different nutritional values, almost none contain caffeine, and many people find these a more palatable option than the bold, take-it-or-leave-it taste of tea.
More often referred to as "Red Tea", rooibos is a rough, brown bush grown primarily in South Africa. The plant is green until it's cut, and it is actually classified as a legume, oddly enough. It is known to contain a very high level of flavonoids, which are believed to prevent cancer by by stabalizing harmful free radicals within the body. 3 Rooibos is also growing in popularity because it is naturally caffeine-free and absorbs flavors from fruits and spices very well, making for a truly enjoyable cup. The photo to the left is of the contents of a bag of rooibos tea---the brand, Kalahari, was purchased at a local grocery store, so although rooibos is a foreign herb, it is relatively widespread in the US now. Yerba Mate
Mate is a South American herb that is sometimes boiled and consumed like conventional teas. It is a natural stimulant that has been used by Guarani Indians in Paraguay in many of their household remedies. "Mate deserves the attention of every person interested in optimum health," said Daniel Mowrey, a doctorate with a Ph.D. in experimental psychology. Yerba Mate has been attributed with boosting immunity, stimulating the mind, curbing the appetite and, oddly enough, restoring youthful hair color. Mate is primarily consumed in the US as a weight control aid, because it is believed to curb appetite.4  Chamomile
This lightweight flower is boiled in cheesecloth and has a strong, sweet smell and a light, sweet taste. Chamomile has long been imbibed as a relaxation tea because it increases levels of glycine, an amino acid that relieves muscles. However, new research has found that drinking five cups of chamomile tea a day increases antibacterial activity in the body.5 Plus, the light taste is perfect for a before-bed beverage.