Enema, or Clystse. Drugs and nutrient material are sometimes administered by injecting them into the lower bowel. Such an injection is termed an enema (from a Greek word signifying to inject). A simple enema prescribed with the object of emptying the lower bowel in constipation usually consists of warm water, or soap-and-water, with the addition sometimes of castor oil. Nutrient enemata are given where food cannot be retained when administered by the mouth; or where, as in stricture of the oesophagus, there is a difficulty in swallowing, and consequently in the passage of nutrient material from the mouth into the stomach.