The parameters of acute oral toxicity of Mastigard® are presented. The drug was introduced intragastrically to rats at a dose of 2000 mg/kg. During the study, the tested dose did not cause signs of intoxication and death of animals. Physiological parameters of rats remained within the species norm. Also no changes in the behavior of animals were noted, the reaction to tactile, pain, sound and light irritants was adequate. Autopsy of animals at the end of observation did not reveal pathological and anatomical changes in internal organs and tissues. Regular control of body weight of rats testified to uniform weight gain of all experimental animals during 14 days of observation, no body weight loss was observed during all periods of weighing. Thus, the LD50 of Mastigard® is more than 2000 mg/kg. Mastigard® belongs to the 5th class of toxicity according to the GHS and the 4th class of danger (substances of little danger) according to GOST 12.1.007-76.