1. Alkaloids in tea can dilate blood vessels, increase cardiac output and make blood circulate effectively, especially theophylline can relax smooth muscle. It can expand the ratio of blood vessels to muscles, so it can treat hypertensive headache.

Second, tea polyphenols in tea, especially catechins, have a strong lipid-lowering effect, which can effectively protect capillaries, relax blood vessel walls, increase effective diameter and enhance elasticity. Even if blood vessels are damaged, tea polyphenols can restore the function of blood vessels. It is beneficial to the relaxation of human blood vessels, enhances the elasticity and toughness of microvessels, and plays a role in preventing cardiovascular and cerebrovascular diseases.