Colonic dialysis uses the colonic mucosa as a semi-permeable membrane to inject dialysis fluid into the lumen of the colon, and removes water and metabolic products retained in the body by diffusion and osmosis through the solute concentration gradient and osmotic pressure gradient in the blood and dialysis fluid in the capillaries separated by the colonic mucosa, and excretes these substances from the body with the dialysis fluid, while replenishing the necessary substances from the dialysis fluid. The dialysis fluid is continuously replaced repeatedly to achieve the therapeutic purpose of toxin removal, dehydration, and correction of disorders of water-electrolyte acid-base balance. The main factors that affect the effectiveness of dialysis are the ionic concentration of the dialysate, the pH value, and the osmotic pressure.