Biliverdin is a green pigment that is produced during the breakdown of hemoglobin, the protein in red blood cells that carries oxygen. When red blood cells age or are damaged, they release hemoglobin, which is then converted into biliverdin through a series of enzymatic reactions. This process occurs primarily in the liver and spleen. Biliverdin plays a role in the body's natural detoxification process. It is eventually converted into bilirubin, a yellow pigment that is excreted in bile. Both biliverdin and bilirubin are important for the body's metabolism and can also have antioxidant properties, helping to protect cells from damage.