In this work, the effect of albendazole and two drugs containing triclabendazole, but characterized by different indices of solubility and bioavailability, on the glycogen content in preimaginal trematodes Fasciola hepatica is considered. This reserve biopolymer of glucose serves as a substrate for energy requirements that increase under stressful conditions for the body, which leads to an increase in its utilization. The effect of anthelmintics was tested with a single oral administration of drugs to rats on the 40th day after the invasion of animals with adolescariae F. hepatica. Active ingredient dosage were 15 mg / kg for albendazole, 5 mg / kg for triclabendazole and 1 mg / kg for the supramolecular complex of triclabendazole with a water-soluble polymer polyvinylpyrrolidone. The concentration of glycogen in fascioli was determined by the spectrophotometric method on the first, second and third days after therapy. In the control group, glycogen was contained in an amount of 0.041 ± 0.002 mg / mg of fasciola. A day after the rats received the drugs, a decrease in the level of glycogen in helminths was observed: to 0.032 ± 0.005 mg / mg after administration of albendazole, to 0.027 ± 0.002 mg / mg after administration of triclabendazole, and to 0.025 ± 0.002 mg / mg after administration of triclabendazole in combination with polyvinylpyrrolidone. The amount of glycogen approached the norm for most of the helmints on the second day after treatment with albendazole, and on the third day after therapy with triclabendazole-containing drugs. Thus, the low effcacy of albendazole against preimaginal Fasciola hepatica was confurmed and the effcacy of triclabendazole at a dose of 5 mg / kg in the form of a substance and at a dose of 1 mg / kg in combination with polyvinylpyrrolidone was compared in terms of the degree of influence of anthelmintics on energy and carbohydrate metabolism, in particular, the glycogen concentration