Objective: Ma'aljobon is used in Persian medicine (PM) as a natural antihypertensive product. This study aimed to evaluate the hypotensive effect of Ma'aljobon in patients with uncontrolled grade 1 primary hypertension (HTN). Materials and Methods: This double-blind, placebo-controlled clinical trial included 114 patients (20-80 years) with uncontrolled grade 1 primary HTN. After obtaining informed consent, the participants were randomly divided into two groups and administered with 25g of Ma'aljobon or maltodextrin twice daily for six weeks. Systolic and diastolic blood pressures (SBP and DBP, respectively) were analyzed. Results: A total of 97 patients (52.3±10.7 years, S.6 female) completed the study. In the Ma'aljobon group, SBP decreased from 150.3±12.3 to 130.6±12.1 mm Hg, and DBP decreased from 93.3±8.2 to 80.1±6.6 mm Hg (p<0.001). In the control group, SBP decreased from 147.6±11.2 to 138.7±14.4 mm Hg, and DBP decreased from 86.6±7.7 to 82.2±8.2 mm Hg (p<0.001). There was a significant difference in the changes of SBP and DBP between the two groups over time (p<0.001). No adverse events were observed. Conclusion: Ma'aljobon has a stronger hypotensive effect than placebo in patients with HTN and can be recommended as an addon therapy for uncontrolled HTN.