To study the role of diet, 197 patients of essential hypertension were randomized to either experimental diet (group A, 97 cases) or normal diet (group B, 100 cases) with diuretics given to both the groups. The age varied between 25 and 65 years and 154 were males. The study diet included a significantly higher content of potassium (K), magnesium (Mg), calcium (Ca), polyunsaturated fat, and complex carbohydrates compared to the normal diet. At entry to the study, age, sex, risk factors, mean blood pressures, mean serum Mg, K, Ca, and Na, and drug therapy were comparable in both groups. After 1 year of follow-up, there were significantly fewer patients with resistant hypertension in group A (5) than in group B (17). Mean systolic (148.22 +/- 10.1 mm Hg) and diastolic (90.2 +/- 4.84 mm Hg) pressures in group A were lowered compared to mean systolic (160 +/- 12.0 mm Hg) and diastolic (103.3 +/- 5.8 mm Hg) pressures in group B and initial mean systolic (152.2 +/- 12.8 mm Hg) and diastolic (99.8 +/- 7.2 mm Hg) pressures. Mean serum magnesium (1.86 +/- 9.22 mEq/l) and potassium (4.86 +/- 0.39 mEq/l) levels in group A were significantly higher compared to mean levels of 1.56 +/- 0.11 and 4.0 +/- 0.29 mEq/l, respectively, in group B. However compared to initial levels, K and Mg showed no significant changes in groups A and B. There was a significantly lower incidence of complications in group A (58) compared to group B (100). It is possible that a diet low in Na/K ratio and rich in complex carbohydrates, polyunsaturates, K and Mg may cause a significant reduction in blood pressure and its complications.