Urobilinogen, also known as urobilinogen, refers to the destruction of old red blood cells in the liver or spleen, and the hemoglobin in the red blood cells becomes bilirubin, which is excreted in the bile into the intestine, where it is broken down by bacteria into urobilinogen. When there is excessive destruction of red blood cells, liver cell damage, intestinal obstruction and stubborn constipation, etc., it can cause an increase in urobilinogen. The normal value of urobilinogen is 0.3-3.55 μmol/L for men and 0-2.64 μmol/L for women, therefore, if the value of urobilinogen is 3.4 μmol/L for men, it is basically in the normal range and there is no need to worry too much. In women, a urobilinogen value of 3.4 μmol/L is indicative of a slightly elevated level. The above values are quantitative tests of urobilinogen, which can more accurately reflect whether urobilinogen is normal and the degree of elevation than qualitative tests. Although an increase in urobilinogen has some clinical significance, it is not possible to determine the cause of this abnormality on its own. Therefore, further blood tests, liver function, virus-related, and hepatobiliary imaging are needed to rule out the presence of obstructive jaundice, such as bile duct stones, bile duct cancer, pancreatic head cancer, and periampullary cancer. In addition, even if the urobilinogen is normal, the presence of a disease state cannot be ruled out, for example, in obstructive jaundice, the urobilinogen is negative, but may be within the normal range when quantified, so symptoms and signs are particularly important to determine the presence of disease.