Hemolysis refers to the breakdown of red blood cells.

Red blood cells normally live for 110 to 120 days and then die. When they die, they are broken down. Some diseases and processes can cause premature breakdown of red blood cells and leave fewer than normal red cells available for transporting oxygen.

Conditions that can cause hemolysis include antigen-antibody reactions, toxins and poisons, and treatments such as hemodialysis and the use of the heart-lung bypass machine. See also hemolytic anemia.