1. Refreshing: Black tea contains caffeine, tea polyphenols and amino acids, which can effectively refresh the mind and promote thinking and memory functions.

2. Antioxidant: Black tea is rich in tea polyphenols, which has antioxidant effect, and can protect the body from free radicals and prevent aging.

3. Lowering blood fat: Tea polyphenols in black tea can lower blood fat and cholesterol and prevent cardiovascular diseases.

4. Promote digestion: Tea polyphenols in black tea can promote gastrointestinal peristalsis and enhance the digestive function of gastrointestinal tract.

5. Antibacterial and anti-inflammatory: Tea polyphenols in black tea have antibacterial and anti-inflammatory effects, which can prevent and alleviate infectious diseases.

Taboo of black tea:

1. Pregnant women: Because black tea contains irritating substances such as caffeine, pregnant women, lactating women and children should not drink too much black tea.

2. Hypertensive patients: Black tea contains caffeine and other ingredients, which may lead to an increase in blood pressure. Hypertensive patients should drink it carefully.

3. Patients with liver disease: Tannic acid in black tea will increase the burden on the liver. For people who already have liver disease, it is not suitable to drink a lot of black tea.

4. Anemia patients: Tea polyphenols and other components in black tea will inhibit the absorption and utilization of iron, so it is not recommended for anemia patients to drink black tea for a long time.

5. Glaucoma patients: Black tea contains irritating substances such as caffeine, which will increase intraocular pressure. Glaucoma patients should not drink more black tea.