1. Refreshing and invigorating: black tea contains caffeine and theanine and other components, which can stimulate the nervous system and invigorate the mind.

2. Protect cardiovascular and cerebrovascular: the tea polyphenols in black tea have antioxidant effects, which can reduce the risk of cardiovascular disease.

3. Reducing fatigue: the multiple nutrients in black tea can restore body energy and relieve fatigue.

4. Improve immunity: antioxidants in black tea can improve immunity and prevent diseases.

5. Lower blood sugar: polyphenols in black tea can promote insulin secretion and help lower blood sugar.

Taboos of black tea leaves:

1. Allergy to caffeine is prohibited: black tea contains caffeine, caffeine allergy should not be consumed.

2. Those who suffer from high blood pressure should not drink more: the theophylline in black tea can stimulate blood pressure, so those who suffer from high blood pressure should reduce the amount of consumption.

3. Pregnant women should not drink: theophylline, caffeine and other components of black tea will affect the health of the fetus, pregnant women should not drink too much.

4. People who do not sleep well should not drink before going to bed: the caffeine and theanine in black tea have an excitatory effect, which can easily lead to difficulties in falling asleep.

5. Migraine sufferers should not drink too much: the caffeine and theanine in black tea can aggravate migraine.