There are several reasons why urine is very yellow: i. When urine is concentrated due to drinking too little water, the phenomenon of very yellow urine can occur. Second, when you have taken B vitamins, the B vitamins are excreted from the urine, which can lead to a very yellow color of urine. Third, the color of urine is very yellow because the bilirubin of urine is high, the urine contains a large amount of conjugated bilirubin, the appearance will appear dark yellow, common in obstructive jaundice as well as hepatocellular jaundice, you can check the liver function to see whether there is high glutathione transaminase, glutamic oxalacetic transaminase, total bilirubin, direct bilirubin, indirect bilirubin, in addition, you can also do liver and biliary ultrasound examination. If there is indeed liver inflammation, such as viral hepatitis, chronic hepatitis B or steatohepatitis, you can target treatment to lower the bilirubin and the urine color will gradually return to normal.