Albendazole oxide (Ricobendazole) is a methylcarbamate benzimidazole with a broad-spectrum anthelmintic activity. Ricobendazole is a key metabolite of albendazole. Ricobendazole has broad spectrum anthelmintic action; the drug is active against adult and immature nematodes (Dictyocaulus, Haemonchus, Ostertagia, Thelazia, Trichostrongylus, Nematodirus, Cooperia, Oesophagostomum, Bunostomum, Chabertia etc.), tapeworms (Moniezia, Avitellinae, Thysaniezia etc.), as well as adult flukes (Fasciola, Paramphistom, and Dicrocoelium), having an egg-killing effect; it reduces pasture contamination with helminth eggs. The mechanism of action of ricobendazole (albendazole sulfoxide), ensuring its anthelmintic activity, is associated with selective inhibition of beta-tubulin polymerization, which leads to the destruction of cytoplasmic microtubules of helminth intestinal cells; it inhibits the processes of glucose transport and disposal, and inhibits the synthesis of ATP; it blocks the movement of secretory granules and other organelles in the muscle cells of worms, disrupting the permeability of cell membranes and muscle innervation, which causes paralysis and death of the parasites. Albendazole oxide has been shown to induce apoptosis in human cancer cell line HT-29, possibly by arresting the cell cycle at the G2/M phase.