Peritoneal dialysis works by using the lining of the belly, called the peritoneum, as a filter. We train families to do this type of dialysis at home. A soft tube (catheter) is used to fill the belly with a cleansing liquid called dialysis solution. Waste and extra fluid in the blood pass through the lining of the belly into the dialysis fluid. The used dialysis fluid then drains out through the catheter and is thrown away.