There is no standardized rule for how much weight loss is normal with interferon for hepatitis B. Generally, a weight loss of 3% or more in a month is considered significant weight loss, and needs to be changed to another medication under a doctor’s evaluation, or checked for other causes. Interferon is an important drug for the treatment of hepatitis B. It has a well-defined role. Some patients can experience significant side effects while taking interferon in the form of fever, chills, headache, muscle aches, nausea, vomiting, etc., especially gastrointestinal symptoms are very pronounced. They usually disappear on their own after 2 to 4 weeks. However, if the discomfort persists, you can consider using some drugs to promote digestion, such as compound pepsin powder, as well as some gastrointestinal mucosal protectors, such as omeprazole. But if the symptoms can not be improved and weight loss is obvious. Discontinuation of interferon and switching to other drugs need to be considered. Also check whether the weight loss is due to hepatitis itself, the presence of other complications or comorbidities. It is recommended that if there is significant weight loss during the use of interferon, it is necessary to consult a doctor in time to identify the cause and target treatment. Do not stop the drug without authorization, the above medication need to follow the doctor’s instructions.