The FDA has approved using fenbendazole in veterinary medicine to treat a broad range of worms in goats, swine, horses, and cattle. The FDA has approved its use for treating whipworms, tapeworms, roundworms, and hookworms. Fenbendazole prevents worms from making energy, which eventually causes the parasite to starve to death. In certain worm species, the condition may also extend to immature life stages like larvae or eggs.