Abana is a herbomineral medicinal preparation with a property of down-regulation of beta-adrenergic receptors. A double-blind, parallel group study was conducted in 43 Indian men and women suffering from hypertension to evaluate the antihypertensive effect of Abana and compare it with that of methyldopa (M-DOPA). Twenty-one patients received 800 mg tds of Abana and 22 patients received 250 mg tds of M-DOPA for 4 weeks. Blood pressure and pulse rate were recorded at weekly intervals. Relevant clinical and biochemical investigations were carried out before and after treatment. In patients treated with Abana, there was a significant fall both in systolic B.P. (from 167 +/- 3.73 to 145 +/- 6.11 mmHg) and in diastolic B.P. (from 110 +/- 1.86 to 91 +/- 3.04 mmHg) at the end of 4 weeks. Similarly in patients treated with M-DOPA, systolic blood pressure was significantly reduced from 165 +/- 4.92 to 146 +/- 4.9 mmHg and diastolic blood pressure was reduced from 106 +/- 2.74 to 96 +/- 2.67 mmHg after 4 weeks. The onset of antihypertensive effect was earlier and there was a higher percentage of responders (80%) in the Abana-treated group. None of the patients had clinically or biochemically significant side-effects. The results of this study suggest that therapy with Abana proved highly effective in hypertensive patients.