Interferon is one of the main antiviral treatment agents for chronic hepatitis B. The benefit of using interferon therapy is the promise of a durable response after a limited course of therapy with discontinuation, which simply means that it is possible to stop the drug. As a result, several recent guidelines, such as the 2012 NICE guideline and the 2015 Asia-Pacific Liver Institute guideline, recommend long-acting interferon as a first-line agent for slow-acting hepatitis B. However, in clinical practice many patients are still afraid of interferon therapy, on the one hand because they are afraid of the hassle of injections, and on the other hand they are always worried about the adverse effects of interferon therapy. For example, prolonged fever and hematocrit are the most frequently mentioned problems. Fortunately, after many years of clinical experience, most of these adverse reactions have been mastered and are completely manageable, and generally do not affect the treatment nor cause additional damage to the patient’s health. Long-term fever and hematocrit are some of the more common adverse reactions to interferon therapy, and the corresponding treatment measures are more mature and effective. Management of prolonged fever. The so-called prolonged fever is a cold-like symptom and is the most common side effect, manifesting as fever, chills, headache, muscle aches and weakness. If these symptoms occur, patients can change the time of interferon injection to bedtime or take oral medications such as aspirin or paracetamol (acetaminophen) along with the injection. Management of neutropenia and thrombocytopenia. Hemocytopenia may occur after interferon therapy. In order to detect the problem in time to give targeted treatment, regular blood tests should be received after interferon therapy, usually every 1-2 weeks at the beginning of the first month, and then once a month until the end of treatment. For example, if the absolute neutrophil count is less than 0.75×109/liter and/or platelets are less than 50×109/liter, the dose of interferon should be reduced; after 1-2 weeks, if the index returns to normal, the dose can be gradually increased to the starting dose. When the absolute neutrophil count is less than 0.5×109/liter and/or platelets are less than 30×109/liter, discontinuation of the drug should be considered. Alternatively, granulocyte colony-stimulating factor or granulocyte macrophage colony-stimulating factor therapy may be used when neutrophils are significantly reduced. In addition to these two types of adverse reactions, common adverse reactions to interferon therapy include mood changes and thyroid disease. However, these adverse reactions are manageable and generally do not affect treatment. Adverse reactions are side effects of drug therapy, and there is no drug that is 100% free of adverse reactions. Slow hepatitis B treatment should not be choked, but according to your own condition, choose a suitable treatment plan, and actively and regularly monitor, you can detect and deal with possible adverse reactions at an early stage to guarantee the efficacy of treatment.