There is a marked difference between an enema and suppository, although they are both used for the relief of constipation in some cases. An enema is a liquid that is inserted into therectum using a nozzle attached to a bag made of plastic or cloth. The liquid is forced into the rectum through this device to relieve occasional constipation or prepare patients for surgery. A suppository is a small solid or semi-solid plug made from a particular type of medication. The most commonly used type is made from glycerin and is used to relieve constipation, although other medicines may also come in the form of a suppository.