The effect of cytoflavin bolus (i.v.) injection on the cardiovascular system was studied in experiment on rats in comparison to adrenaline. A total of 18 rats were divided into two groups: 12 rats in the test group were injected cytoflavin bolus into the tail vein at 1.5 mL/kg; 6 rats in the control group were injected adrenaline (epinephrine) bolus at 0.1 mg/kg for the comparison, as this drug is used in clinical practice for hypotension treatment. Cytoflavin increased the median arterial pressure (AP) by 9% in 5 min after injection, and the effect was similar to that produced by epinephrine. At 10 and 15 min after cytoflavin administration, the AP increase was less pronounced than in the group treated with epinephrine, and was not accompanied by tachycardia in contrast to the case of epinephrine administration. Cytoflavin reliably decreased R wave voltage by 24% (p = 0.045), while epinephrine decreased R wave voltage by 28 % (p = 0.046) relative to the baseline. In 20 min after cytoflavin administration the heart rate remained unchanged, while that in the group injected with epinephrine was clearly increased by 5.5% (p = 0.05).