Clyster apparatus which uses tobacco smoke. An enema or clyster, is a fluid injected into the lower bowel by way of the rectum. The most frequent use of an enema is as a cleansing enema (also called a soapsuds enema) which is given to relieve constipation or for bowel cleansing before a medical examination or procedure. Etching from " La Presse medicale", 1903.