Dialysis tubing is a semipermeable membrane used in medicine to remove toxins from a patient's bloodstream. It is also used in classroom experiments to demonstrate osmosis and pressure gradients across a membrane. The tubing consists primarily of cellulose, an organic polymer.
Dialysis tubing is used primarily for kidney dialysis, which treats patients with limited or lost kidney function. The tubing, attached to a dialysis machine that works to rid the blood of toxins, aids in the removal of waste product molecules by circulating the blood from the patient through the machine and then back to the patient. This process cleans the blood just as a normally functioning kidney would.