Urobilinogen is a chemical compound that is derived from the breakdown of bilirubin in the liver. There are several synonyms for urobilinogen, including urobilin, urobilinuria, and porphyrin. Urobilin is a yellow pigment that is formed in the intestine after the breakdown of hemoglobin. Urobilinuria is the presence of urobilin in the urine, which can indicate liver or gallbladder problems. Porphyrin is a group of organic compounds that are involved in the synthesis of heme, a component of hemoglobin. Overall, these synonyms for urobilinogen are essential in determining the health of the liver and identifying potential medical conditions.