Aim: The aim of the present study to evaluate the efficacy and tolerability of vitamin C as add on therapy to standard antihypertensive regimen. Methods: A comparative prospective study was conducted in the Department of Pharmacology, Anugrah Narayan Magadh Medical College and Hospital, Gaya, Bihar, India for 1 year. The study was undertaken in mild to moderate hypertensive patients to find out the efficacy and tolerability of vitamin C as an add-on therapy to the standard anti-hypertensive regimen in the reduction ofblood pressure and C-reactive protein levels. Total 160 patients with systolic blood pressure in the 140-179 mm Hg range and diastolic blood pressure in the 90- 109 mm Hg range with C-reactive protein levels in the 10-12 mg/dl range were recruited for the study out of 720 patients screened. Results: Out of 720 patients screened, 160 patients were included in this study. They were randomized into four groups, group 1, group 2, group 3 and group 4, each consisting of 40 patients. In group 1, mean age was 44.22±6.88, group II 44.97±9.87, group III 47.01±7.23 whereas in group 4 45.14±6.81. On comparison we found non-significant difference with P value.At baseline there was non-significant difference among all the four group with p value 0.25, whereas at all the visit at 1, 3 and 6 month there was significant difference among the four group with p value <0.01, <0.001 and <0.001. At baseline there was no significant difference among different groups in diastolic BP, whereasthere was significant difference among all four groups at all 3 visit i.e 1, 3 and 6 months with p value<0.001. Conclusion: Vitamin C at the dose of500 mg OD as an add on therapy to enalapril 5 mg BD causes significant reduction of both systolic and diastolic blood pressure, vitamin C 500 mg OD supplementation to the standard anti-hypertensive drugs may produce better reduction of blood pressure, vitamin C 500 mg may be recommended as an adjuvant to regular antihypertensive regimen to reduce cardiovascular and cerebrovascular risks associated with hypertension.