One of the most effectual vermifuges; that is, medicines which either kill or drive out worms. It must be used with care, as excessive doses are violent in their action; we may say poisonous. For lumbricord worms, the commonest kind, one grain will be a dose for an adult; a quarter of a grain, or less for a child. For seatworms (those small ones which inhabit the lower bowel; and cause annoying itching of the anus or outlet) suppositories of santonin are the best remedy. These are made of cocoa butter, with two or three grains of santonin in each; one being inserted into the bowel at bedtime.