To maintain sustainable veterinary welfare, food and economic security of the country, it is necessary to create new highly effective medicines. The problem of improving the quality and safety of livestock products indicates the advisability of developing medicines aimed at combating ectoparasites of farm animals, because in some zones of Russia, including Siberia, this problem is very acute. A prerequisite for the use of new drugs in veterinary medicine is the prior conduct of toxicological studies on laboratory animals. The article presents data on the study of the acute toxicity of the drug Delcid 7.5® when administered by cutaneous administration in white male rats. The drug is manufactured by LLC NVC Agrovetzashchita, it is an oily transparent liquid in the form of a solution for external use. As active ingredients it contains: deltamethrin - 7.5 mg, diflubenzuron - 3 mg and piperonyl butoxide - 1.5 mg, as well as auxiliary substances: butylhydroxytoluene, butylhydroxyanisole, diethylene glycol monoethyl ether. In the course of the research, a clinical ex amination of the animals was carried out. Observations were carried out for changes in the condition of the skin and hair, eyes, mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behavior. At pathological autopsy, attention was paid to the state of the internal organs. The parameters of the acute toxic effect of the drug were calculated. The maximum tolerated dose, absolutely lethal and average lethal dose (LD50) of the drug Delcid 7.5® in male rats have been established. According to the degree of impact on the body according to GOST 12.1.007-76, this drug belongs to the 3rd hazard class - moderately hazardous substances.