SCT and essential hypertension: Animal experiments have shown that ZGXFD could lower blood pressure, inhibit the expression of angiotensin II, endothelin, secretin, and somatostatin in rats with essential hypertension,[17,18] and the apoptosis of vascular smooth muscle.[19] Clinical researches have also shown that there is good curative effect for ZGXFD in the treatment of essential hypertension [20,21]; however, there is a lack of systematic review and meta-analysis regarding its efficacy and safety.