Adefovir was approved for the first-line treatment of chronic hepatitis B in the United States in September 2002 and marketed in China in April 2005. It is an acyclic nucleoside analogue of adenosine monophosphate, which is phosphorylated into an active metabolite, adefovir diphosphate, by inhibiting the activity of HBV-DNA polymutase and acting as an anti-hepatitis B virus replication, and is very effective in HBeAg-positive, HBeAg-negative and lamivudine-resistant chronic hepatitis B patients have significant efficacy, low hepatitis B virus resistance mutation rate, good tolerability, and very commonly used clinically. In contrast, hypophosphatasia caused by adefovir has an insidious onset and is easily overlooked by everyone. Please pay attention to review the blood phosphorus if you experience pain and weakness in both lower extremities while taking adefovir, and go to a specialized hepatology clinic for treatment if it decreases.