Normal tea drinking does not affect blood pressure, but if you drink a lot of strong tea may increase blood pressure, related to the theophylline content of tea. Tea contains many substances, such as protein, carbohydrates, theophylline, polyphenols, amino acids, vitamins and minerals. Theophylline in tea causes sympathetic nerve excitation, which in turn causes an increase in blood pressure. Drinking a small amount of tea will not normally cause an increase in blood pressure, but when drinking a large amount of tea or drinking strong tea, resulting in excessive intake of theophylline, it may lead to an increase in blood pressure. Therefore, it is recommended that the public drink a moderate amount of tea and avoid drinking strong tea, especially for hypertensive patients, so as not to cause discomfort after the rise in blood pressure.