High alanine aminotransferase 42 is slightly high and usually not very serious. The normal value of alanine aminotransferase is 0-40 u/l, which is mainly found in hepatocytes, and is an important indicator for the diagnosis of viral hepatitis and toxic hepatitis. Factors such as overwork, lack of sleep, colds, excessive alcohol consumption, medication, and heavy exercise may lead to a transient increase in alanine aminotransferase. However, if it is high for a long period of time and far away from the normal value, for example, elevated to two to three times, it usually suggests the possibility of liver injury, such as viral hepatitis, fatty liver, myocardial infarction, cirrhosis, myocarditis, etc., which will make the transaminase increase. If you have a high transaminase, you should go to the hospital in time to have a relevant examination to clarify the cause of the disease and follow the doctor’s instructions for treatment to avoid serious consequences.