Diseases of the skin, inflammation, complications of suppurative processes can be caused by invasion of akariformes and lead to the deterioration of animal health, slimming and intoxication. The aim of this work was to investigate the efficacy of the drug “MEGA STOP” by analyzing the clinical status of the animals and the dynamics of hematological parameters. It was used 15 animals aged from 8 months to 5 years, of both sexes. Examined the General condition of the animals (behavior, reaction to external stimuli, presence of appetite, skin and coat, the color of the mucous membranes and the like). It was performed microscopic examination of scrapings from the affected skin and ears, as well as clinical analysis of blood. The drugs were applied according to the instructions and the invasion of intact skin. In all animals with a flea in a single treatment was effective. The blood counts were normal (the upper and lower lime), except for erythrocytes (below normal from 4.72 % to 2.26 %). It was established, that all animals treated with the drug MEGA STOP at 0 day was deviation in the norm of the indicator red blood cells to decrease from 0.4 of 7.36 %. In the following days of the study (10 and 20 day), indicators are normalized and the condition of the animals improved. The maximum deviation of the blood parameters from the norm were detected in an animal with double invasion (otodectosis and fleas). The study of the animals before treatment were violations of the skin in the affected areas of agents, anemia, leukocytosis and eosinophilia. These changes of the blood, characteristic of allergic and intoxication metabolites acariformes. After the first treatment the condition of the ears and skin, according to the results of clinical examination and microscopy, have improved as the blood counts. After the second treatment the animals of both groups a swab from the ears clean and no clinical manifestations. The high efficacy of the drug “MEGA STOP” for the prevention and treatment of flea infestations and acarosan (notoedres, otodectosis in, demodicosis) in single/double skin applied depending on the degree of infestation.