Butyl chloride is an alkyl halide. It is used as a butylating agent in organic synthesis, e.g., in the manufacture of butyl cellulose. n-Butyl chloride is a veterinary antiparasitic (anthelmintic) drug. It is used for the removal of ascarids and hookworms from dogs and cats. n-Butyl chloride is marketed under tradenames NBC Kaps Wormer for dogs, Happy Jack Worm for dogs; Sergeants Sure Shot Capsules for cats and dogs.