Taking entecavir does not cause abnormal liver function, and the most common adverse reactions to entecavir are headache, fatigue, dizziness, and nausea. Entecavir belongs to the nucleoside class of drugs, has the effect of inhibiting the replication of hepatitis B virus, and is used to treat chronic viral hepatitis B. If chronic viral hepatitis B turns negative after 1 year of entecavir treatment, but the liver function is still abnormal, further examination is needed to rule out other causes of abnormal liver function, such as fatty liver and autoimmune liver disease. Entecavir does not have the side effect of abnormal liver function. The most common adverse reactions after taking entecavir are headache, fatigue, dizziness, and nausea, which are mostly mild and gradually relieved after taking it for a period of time. In some patients, long-term use of entecavir can lead to elevated lactic acid. The drug needs to be taken under the guidance of a doctor, avoid taking the drug on your own.