Also known as the red bush, rooibos is a plant native to Southern Africa and perhaps its most popular use is for herbal tea. It does not have caffeine naturally and a health benefit of interest to many is the fact that it has low tannin content. Tannins are what give teas their bitter taste and large amounts can cause digestive side effects and even liver damage. Some research has linked high consumption of tannins with a greater risk of nose and throat cancer. However the research is inconclusive as there is plenty which contradicts and actually points to tannins having anti-cancer activity.
Rooibos tea antioxidants include aspalathin, dihydrochalcones, nothofagin, and other polyphenols. How much antioxidants they have in total is less than most non-herbal varieties like black tea and green tea.
While it has been enjoyed for many generations in South Africa, its popularity in most other parts of the world is relatively new. As recently as the 90's, it was almost unheard of in the United States. Today, rooibos tea is one of the most popular herbal choices. Likewise for the United Kingdom, where it is commonly referred to as redbush tea.
Research Support, Non-U.S. Gov't: Carlsen MH, Halvorsen BL, Holte K, et al. Nutrition Journal NIH Jan 2010