Abstract: AIM: To evaluate the efficacy and safety of compound lisinopril tablets (domestic product) in patients with mild-to-moderate essential hypertension. METHODS: A double-blind, randomized clinical trial was conducted. Patients with essential hypertension (n=98) were treated with placebo for 2 weeks and then lisinopril (10 mg/day) for 4 weeks. Those patients whose blood pressure was still not <140/90 mmHg (n=49) were randomly assigned to receive lisinopril 20 mg, 1/day (control group, n=25) or compound lisinopril tablets (compound group, n=24, lisinopril 10 mg/hydrochlorothiazide 12.5 mg, 1 tablet/day) for 8 weeks. RESULTS: No significant difference was seen in the effective rate between groups (88% and 84%, in compound group and control group, respectively). Adverse reactions were slight and the most common was cough (17% and 20%, in compound group and control group, respectively). CONCLUSION: Compound lisinopril is proven to be safe and effective as an antihypertensive.