The U.S. FDA lists the following as contraindications for colon hydrotherapy:

Cancer of the colon or GI tract

Acute abdominal pain

Recent history of gastrointestinal bleeding

Congestive heart failure

Uncontrolled hypertension

History of seizures

Abdominal surgery

Diverticulitis

Recent heart attack

General debilitation

Recent colon or rectal surgery

Vascular aneurysm

Renal insufficiency

Epilepsy or psychosis

Cirrhosis

Carcinoma of the rectum

Severe hemorrhoids

Intestinal perforation

Fissures or fistula

Abdominal hernia

This list is not exhaustive. A thorough health intake and consultation are required prior to treatment. Based on your health history and current condition(s), treatment may need to be postponed or require written medical clearance.