Eating betel nut affects blood pressure. The tannins extracted from betel nut seeds inhibit angiotensin-converting enzyme, which has a blood pressure-lowering effect. Known chemical components in betel nut, such as betel nut alkaloids, catechins and so on have some blood pressure lowering effect, betel nut alkaloids can also inhibit cardiac activity and dilate blood vessels. Catechins not only dilate blood vessels, but also properly antiplatelet activity, so it is helpful for cardiovascular system diseases. Betel nut alkaloids have cholinergic receptor effects, which can inhibit cardiac activity, thus lowering blood pressure. Betel nut alkaloids also have anti-atherosclerotic, hypoglycemic and lipid-regulating effects. However, eating betel nut does not increase the tannin content, betel nut alkaloid content and catechin content significantly, it can only be said that eating betel nut may help blood pressure, but not by just eating betel nut to reduce blood pressure, to achieve the purpose of treating hypertension.