Studies on the acute, subchronic and chronic toxicity of technical tylosine phosphate (TTP) with 50 UI/mg activity, produced by Pharmachim were carried out. It was established that TTP does not cause lethality in white rats following application of 20, in white mice--of 40, in chickens--of 30 and in pigs--of 2 g/kg body weight. Long term application to the rations--of chickens for 40 days, in doses of 20, 40 and 60 g/kg fodder (=1.3 and 5 ED100) and of pigs for 32 days in doses of 2.6 and 10 g/kg fodder (=1.3 and 5 ED100) stimulates gain in weight of both species by 2-11.5% and improves the utilization of nutrition by 4.5-12.5% without any unfavourable effect on the clinical-biochemical composition of the blood and the structure and development of inner organs.