Also known as: Camellia senensis, English tea.
Potential uses: It is thought that black tea may reduce the risk of several types of cancer, including breast cancer. It is also used to ease stomach disorders such as vomiting and diarrhea and to reduce the risk of kidney stones. Black tea is also used as a diuretic to get rid of excess water in the body.
Usual dose: 1 to 4 cups daily.
Are there any risks? Black tea has about 55 milligrams of caffeine per cup, so it can cause sleeplessness, nervousness, restlessness, stomach upset, nausea, vomiting, and fast breathing. Large doses can produce headache, nervousness, and an increased heart rate.
What does the research show? Black tea contains antioxidants, which offer protection from free radicals. But the studies done so far in humans have shown that black tea does not reduce the risk of breast cancer or any other type of cancer.