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 chemical reactions. This process occurs primarily in the liver and spleen. Biliverdin plays a role in the body's natural recycling of iron and is eventually converted into bilirubin, a yellow pigment that is excreted in bile. Both biliverdin and bilirubin are important for maintaining healthy liver function and can be indicators of various medical conditions when present in abnormal levels.