What does an enema involve?

An enema involves the introduction of fluid into the rectum and lower colon for therapeutic, diagnostic, or cleansing purposes. This procedure is commonly used to relieve constipation, administer medications, or prepare a patient for certain medical examinations and procedures, such as a colonoscopy. The fluid introduced can include saline, water, or specific solutions as needed for the patient's condition.

This option accurately depicts the fundamental nature of an enema and its primary function within the medical and healthcare setting. Other alternatives do not pertain to the definition or purpose of an enema. For instance, dialysis is a procedure used to remove waste products from the blood when the kidneys are not functioning properly, which is significantly different in both technique and application. A type of diet refers to nutritional guidelines followed for health or medical reasons and does not relate to the physical act of administering fluid rectally. Administering medication through the mouth is a common method of delivering drugs but does not encompass the methods or intentions of an enema.