Normally, if liver function is impaired, it will be manifested as weakness, nausea, vomiting, and yellowing of skin and sclera in some patients. These are the precursor symptoms caused by the deterioration of liver function, at this time, patients should further investigate the causes of liver function damage. If the blood test for liver function suggests that alanine aminotransferase and glutamic aminotransferase are elevated, combined with the elevation of bilirubin, according to the type of bilirubin elevation, further correlation tests should be performed to see the possible causes of the underlying liver disease. First, the patient should rule out the possibility of viral hepatitis, and blood should be drawn for hepatitis B trisystems as well as hepatitis C antibodies, to see if the patient has hepatitis B or C. Second, the patient should be checked for autoimmune antibodies, if necessary, to see if there is a possibility of self-immune liver. Then, if necessary, the patient should have an ultrasound of the upper abdomen or an MRI of the upper abdomen to see if there is a possibility of biliary tract obstruction. The most common cause of biliary obstruction is the possibility of choledocholithiasis. Finally, the patient needs to rule out the possibility of obstruction caused by a tumor in the biliary system or the possibility of obstructive jaundice due to compression of the bile ducts by a tumor in the patient’s pancreas.