ACE and essential hypertension: Currently, there are several systematic reviews published regarding the effect of Chinese herbal medicine on primary hypertension, which indicated that Chinese herbal medicines (e.g., the liuwei dihuang pill and tianma gouteng yin) were effective and safe for primary hypertension when compared with conventional treatments (e.g., diuretics, beta-blockers, calcium-channel blockers, and ACE inhibitors) [11–13], but the quality of evidence were unclear.