a helminthic disease of domestic and wild animals (rarely of man), caused by the lancet fluke Dicrocoelium lanceatum. It occurs almost everywhere. The body of the parasite is flat and lancet-shaped, 5–15 mm long, and has pointed ends. The helminth develops with the participation of intermediate hosts, land mollusks, and second intermediary hosts, ants. Swallowing the ants with their feed, the animals are infected with dicrocoeliosis. Parasitizing the bile ducts of the liver and the gall bladder, the fluke causes them to become inflamed. The animals lose weight, their productivity decreases, and they often die. Anthelmintics, chloxylum, and Hetol are used in treating the disease. Extermination of mollusks and ants by agrotechnical means (plowing pastures, planting pastures with cultivated crops) and biological ones (keeping chickens in the field) exert a substantial prophylactic effect against dicrocoeliosis.