Patients who take Entecavir for a long time may experience the following side effects: a. fatigue, headache, nausea, rash, etc., which are generally mild and do not affect life; b. sleep disorders, some people will have difficulty falling asleep or sleep becomes shallow, sleep time is shortened, easy to wake up early, sleep quality is significantly lower than before, after stopping the drug can basically return to normal; c. there may be lactic acid Acidosis, more common in patients with decompensated cirrhosis; 4. Some patients may have abnormal renal function, manifesting as rising creatinine, urinary microalbumin and decreasing glomerular filtration rate. But overall the side effects of entecavir are very mild and rare, and it is still a very good first-line antiviral drug for clinical use.