This article describes studies of the veterinary anthelmintic preparation Moxistop (tablet) for dogs and cats. The preparation Moxistop (tablet) has a wide range of action, thanks to its unique formula moxidectin + praziquantel fights 13 types of parasites, including microfilariae (Dirofilaria repens, Dirofilaria immitis), it is used for prophylactic and therapeutic purposes in nematodes and cestodes. Analysis of the dynamics of clinical indicators of the blood of cats showed that the animals of the first and second groups, all indicators were normal. Eosinophils before deworming in animals of the first group were increased and amounted to (8.2 ± 0.93) % (normal (2–6) %), and after deworming to the 14th day decreased to (4.7 ± 0.51) %; in cats of the second group decreased from (9.7 ± 1.14) % to (5.5 ± 0.49) %. According to the study, it was found that in the studied dogs of one group after the use of the preparation “Moxistop” tablet blood hemoglobin tended to increase relative to normal, namely by 28%, and in group V within normal limits. The content of erythrocytes, leukocytes, eosinophils, lymphocytes and ESR – within normal limits. It should be noted that before deworming in animals of the fourth group, blood parameters, namely eosinophils, were at the upper limit of normal and were (7.9 ± 2.63) % (normal (2–8) %), and after deworming to 14 on the th day decreased to (5.4 ± 1.44) %; in dogs of the fifth group decreased from (7.1 ± 1) % to (4 ± 1) %, in animals of the control group was more than 7 %, which is the upper limit of normal. According to the results of the tests, it was found high efficiency of the preparation “Moxistop” (“Moxistop mini”, “Moxistop copper”, “Moxistop maxi”) in the infestation of Dipylidium caninum, Toxascaris leonina and Dirofilaria immitis in dogs and cats of different ages.