Arterial hypertension (AH) is a multifactorial disease that is accompanied by the development of oxidative-nitrosative stress and insufficient production of hydrogen sulfide (H2S). We hypothesized that garlic bio supplement Full Spectrum Garlic (Swanson Health Product, USA) may be used as a potential H2S donor in treatment of AH in patients. The aim was to study the effect of garlic on blood pressure, ROS generation and cNOS/iNOS activity, biochemical in male 28-39 years old patients with grade II AH. It was found that 10 days of standard antihypertensive therapy (adrenoblockers, ACE inhibitors) with 30 days of garlic supplementation reduced mean systolic and diastolic pressures by 9 and 8 mm Hg respectively. Positive effects of garlic consumption on hemodynamic parameters were observed: enddiastolic volume increased by 8% and peripheral vascular resistance decreased by 11,3% . In the blood plasma of patients, H2S levels increased by 43,6% , the production of ROS and the content of lipid peroxidation products decreased significantly. It is important that the cNOS activity was increased by 130% and iNOS activity decreased by 38,3%. No significant changes in cholesterol, urea, creatinine, glucose, as well as erythrocyte parameters were observed, which indicates the tolerance of the garlic supplements. Thus, the hypotonic effect of garlic is realized by increasing endogenous H2S in plasma, improving endothelium-dependent relaxation of blood vessels and reducing the manifestations of oxidative stress, which makes it promising to use it in the complex therapy of hypertension.