Although drinking tea is beneficial, for some special groups, frequent tea consumption can also produce some adverse effects. When weighing the pros and cons, drinking less tea might be better.

1. People with constipation. The polyphenols in tea have a certain constricting effect on the gastrointestinal mucosa, which can affect the digestion and absorption of food, cause dry stools, and worsen constipation.

2. People with neurasthenia or insomnia. The caffeine in tea has a clear stimulating effect on the human central nervous system. Drinking tea, especially strong tea, can keep the brain in an over-excited state without rest.

3. People with anemia. The tannic acid in tea can cause iron from food to form precipitates that are not absorbed by the body.

4. People with calcium deficiency or fractures. The alkaloids in tea can inhibit the absorption of calcium in the duodenum. At the same time, they can promote the excretion of calcium in urine, leading to less calcium intake and more output, resulting in calcium deficiency or osteoporosis, making fractures harder to heal.

5. People with stomach ulcers. The human stomach contains an enzyme called phosphodiesterase that inhibits gastric acid secretion by gastric wall cells. The theophylline in tea reduces the activity of phosphodiesterase, causing gastric wall cells to secrete large amounts of gastric acid.

6. People with gout. The tannic acid in tea can worsen the patient's condition, so it is not advisable to drink tea, especially tea that has been steeped for too long.

7. People with hypertension or heart disease. Tea contains caffeine, which has a strong cardiotonic and stimulating effect on the human body. This stimulation process can affect the body's physiological activities and increase certain basal metabolic rates.

8. People with fever: When a person has a fever, their heart rate increases and blood pressure is higher than usual. Theophylline can cause body temperature to rise more quickly. In addition, tannic acid directly affects sweat secretion, hindering normal heat dissipation.