Fenbendazole is a broad spectrum benzimidazole anthelmintic used against gastrointestinal parasites including: giardia, roundworms, hookworms, whipworms, the tapeworm genus Taenia (but not effective against Dipylidium caninum, a common dog tapeworm), pinworms, aelurostrongylus, paragonimiasis, strongyles, and strongyloides that can be administered to sheep, cattle, horses, fish, dogs, cats, rabbits, most reptiles.