Bilirubin is the main bile pigment in human bile. Bilirubin is the main metabolite of iron porphyrin compounds in the body and is an important basis for determining jaundice or an important indicator of liver function. The normal range of total bilirubin is between 3.4 and 17.1 μmol/L. Elevated total bilirubin mainly indicates jaundice or liver function. Elevated total bilirubin is a sign of liver damage and indicates liver failure. Patients may present with jaundice, ascites, and coma. Pathologically elevated bilirubin in neonates can also lead to impaired brain function. Treatment with anti-inflammatory, hepatoprotective, cholagogic and anti-yellowing drugs is indicated. Low total bilirubin may be due to a deficiency of a mineral or trace element. For example, iron deficiency can lead to abnormal hemoglobin synthesis, resulting in low total bilirubin. A high or low total bilirubin may indicate an abnormality in the body, and should be treated promptly in a hospital to determine the cause.