Bile pigment; Hemetoidin; 2,17-Diethenyl-1,10,19,22,23,24-hexahydro-3,7,13,18-tetrametyl-1,19-dioxo-21H-biline-8,12-dipropanoic Acid; Bilirubin IXα; 3-{2-({3-(2-carboxyethyl)-5-[(3-ethenyl-4-methyl-5-oxo-1,5-dihydro-2H-pyrrol-2-ylidene)methyl]-4-methyl-1H-pyrrol-2-yl}methyl)-5-[(4-ethenyl-3-methyl-5-oxo-1,5-dihydro-2H-pyrrol-2-ylidene)methyl]-4-me thyl-1H-pyrrol-3-yl}propanoic acid

Principal pigment of bile and constituent of many biliary calculi.