Abstract. Cardiovascular diseases are most common in older people. The functional state of the vascular endothelium is important in the pathogenesis of cardiovascular diseases. Numerous physiologically active substances with different mechanisms of action can affect endothelial function L-arginine, inosine and meldonium caught our attention. Combination therapy is a promising direction in treating circulatory system diseases. This work aimed to establish the age-related characteristics of L-arginine, inosine and meldonium and their combination (Melarginine) on the vascular wall reactivity in adult and old rats to substantiate the occurrence of these cases in cardiology and geriatrics. Experiments were carried out on isolated norepinephrine (10-7 mol/l) segments of the thoracic aorta of adult (8-10 months) and old (21-23 months) outbred male rats. It was shown that the vasodilatory effect of L-arginine, inosine and meldonium and their combination (Melarginine) was insignificant. At the same time, the isolated vascular segment relaxation of old rats under the studied substances was significantly greater compared to adult animals. It should be noted that the vasodilatory effect of acetylcholine in old rats was significantly less than in adults. This indicates the practical endothelium preservation in adult animals and its damage in old ones. The greater sensitivity of the vascular wall of old rats to the action of L-arginine, inosine and meldonium and their combination Melarginine indicates their action is directed at restoring endothelial function in old animals. This suggests the feasibility of using Melarginine in geriatric practice for cardiovascular disease treatment in the future. _________________________________________________________________________________________ Keywords: vessel reactivity; ageing; L-arginine; inosine; meldonium; Melarginine