Dialysis, peritoneal: A dialysis technique that uses the patient's own body tissues inside the belly (abdominal cavity) as a filter. The intestines lie in the abdominal cavity, the space between the abdominal wall and the spine. A plastic tube called a dialysis catheter is placed through the abdominal wall and into the abdominal cavity. A saline fluid called dialysate is then flushed into the abdominal cavity so that it washes around the intestines. The intestinal walls act as a filter between this fluid and the bloodstream. By using different types of solutions, waste products and excess water can be removed from the body through this process.