Black tea is a fully fermented tea. Regularly drinking black tea is basically harmless to human health, and many people drink it almost without thinking. However, it is important to remind everyone that some people, or in certain specific situations, it is better to avoid drinking black tea.

1. Stomach heat. Black tea is fully fermented and inherently warm in nature, providing a warming effect on the stomach. Therefore, those with stomach heat should not add fuel to the fire.

2. People with sensitive nerves and those prone to insomnia. For such individuals, drinking black tea can further stimulate nerve sensitivity and worsen insomnia.

3. Stones. People suffering from stones are generally advised not to drink black tea.

4. Bad breath, internal heat (上火), etc. Due to its warm nature, people experiencing internal heat should avoid drinking black tea.

5. Women during special periods, such as menstruation, pregnancy, and menopause. Drinking black tea during these times can have some adverse effects on the body.