What Is Black Tea? Black tea is made from the leaves of a bush called Camellia sinensis. It has caffeine as well as other stimulants and antioxidants. Lots of people in the U.S. drink it either hot or cold. It should always be steeped in hot water before it is cooled. A process called oxidation turns the leaves from green to a dark brownish-black color. Oxidation means the leaves are exposed to moist, oxygen-rich air. Tea manufacturers can control the amount of oxidation. Black tea is a fully oxidized tea. Green tea comes from the same plant, but is not oxidized. Black tea extract is sometimes sold as an herbal supplement. Sometimes, the supplement includes other types of herbs, vitamins, or minerals.

Black Tea Benefits Many people drink black tea just because they like it. People also may use it for: Alertness and energy

Antioxidants, including polyphenols and catechins

Possible anti-cancer effects

Heart health

Improved metabolism

Gut health More research is needed, but there’s some evidence drinking black tea regularly may lower your risk for these conditions: Diabetes

High cholesterol

Kidney stones

Parkinson’s disease

Osteoporosis

Cavities (Dental caries)

Black Tea Risks Drinking black tea in moderate amounts is generally safe for most people. There’s no known right amount to drink. Supplement ingredients and quality may vary widely. This makes it hard to set a standard dose. Drinking large amounts of black tea -- more than four or five cups a day -- may cause health problems. That's mostly because of caffeine-related side effects. Side effects of black tea (most often in high amounts) may include: Anxiety and difficulty sleeping

Faster breathing

Headache

Increased urination

Irregular heartbeat

Nausea and vomiting

Nervousness and restlessness

Ringing in the ears

Tremors

High blood pressure

Anemia Combining black tea with other types of caffeine or a product called ephedra can be very dangerous. Some of the problems it can cause include: Jitteriness

Increased blood pressure

Heart rate changes

Seizures

Passing out Black tea or black tea supplements may interfere with other medicines and supplements you are taking. Some medicines can also cause caffeine to stay in your body longer than usual. Talk to your doctor to find out if any medicines you are taking may have this effect. The caffeine in black tea may also interfere with certain blood tests. Always tell your doctor about any supplements you are taking, including natural ones and those bought without a prescription. Let your doctor know if you drink a lot of black tea. If you use supplements with black tea, keep in mind that the FDA does regulate dietary supplements; however, it treats them like foods rather than medications. Unlike drug manufacturers, the makers of supplements don’t have to show their products are safe or effective before selling them on the market.