Objective of research: to study the efficacy of supramolecular complexes of Phenasalum at monieziasis in cattle. Materials and methods: After helminthoovoscopic examination of feces by Fülleborn’s flotation method and evaluation of extensity and intensity of invasion, we have selected and formed according to the principle of analogs, 5 groups (10 heads each) of Kazakh white-headed calves at the age of 6–7 mo. Animals in experimental groups received drugs orally as a single dose. Calves of the first group received a supramolecular complex of Phenasalum with Polyvinylpyrroli done (PVP) in the ratio 1:2 at a dose of 20 mg a.i./kg (60 mg/kg of the body mass). The second group of animals was given a complex of Phenasalum with Arabinogalactan (AG) in the ratio 1:2 at a dose of 20 mg a.i./kg (60 mg/kg of the body mass). Calves of the third group received a complex of Phenasalum with SiO2 in the ratio 1:5 at a dose of 20 mg a.i./kg. Animals of the fourth group — complex of Phenasalum with Arabinogalactan (AG) in the ratio 1:5 at a dose of 20 mg a.i./kg and 120 mg/kg of the body mass. Animal of the fifth group didn’t receive anthelmintics and served as controls. 14 days after giving the tested drugs, fecal samples were collected from all animal groups and helminthoovoscopic examinations were carried out. Results and discussion: The experiment showed that at the supramolecular complexes of Phenasalum with Polyvinylpyrroli done (PVP) in the ratio 1:2 and Phenasalumwith Arabinogalactan (AG) in the ratio 1:2 at a dose of 20 mg a.i./kg were the most effective at monieziasis in cattle. The efficacy of the complex of Phenasalum with SiO2in the ratio 1:5 was 74 %. The doses of tested drugs (20 mg a.i./kg) were 5 times less than that of the based Phenasalum (100 mg/kg).