The experiment was performed on 15 rabbits weighing 1.6 - 2.2 kg. The solution of vanadyl sulfate was prepared from spectrally pure salt, and was administered 30 times to the animals, subcutaneously, during the day for two months, in the amount of 1 mg/kg of weight. In order to estimate the toxic effect of the preparation during multiple long-term administration, special investigations were made: there was a general analysis of the blood, blood cholesterol, and beta-lipoproteins. Moreover, 15 amino acids and protein fractions of the blood were investigated in 8 rabbits. All of the investigations were made in dynamics. During clinical observation, the behavior of the animals and outward appearance was no different from the control animals, and there were no disruptions of function of the gastrointestinal tract.