Alanine aminotransferase is an enzyme involved in the metabolism of proteins in the body. It is like a catalyst for industrial production, and alanine aminotransferase serves to accelerate the conversion of proteins and amino acids in the body. Elevated alanine aminotransferase often indicates a liver problem and requires active treatment to identify the cause. If the alanine aminotransferase is one of the liver function tests, it is rarely elevated alone, but is usually accompanied by simultaneous elevation of glutamic oxaloacetic aminotransferase, glutamyl aminotransferase, alkaline phosphatase, etc. A single elevation that does not exceed half of the upper limit of normal value can be temporarily observed and then treated accordingly. There are many causes of liver damage, including hepatitis, alcoholic liver disease, drug-related hepatitis, fatty liver, liver cancer, etc., which need to be diagnosed and treated accordingly, and the means of examination include liver ultrasound, CT, MRI, blood fetoprotein and other laboratory tests. To sum up, if there is an elevated alanine aminotransferase, the cause should be actively identified and treated accordingly.