Background: Chronic hepatitis B is among the prevalent causes of chronic hepatitis and cirrhosis. The aim of this article is to discuss the indications for treatment, available drugs, and identify drug resistance or intolerance and primary treatment failure in chronic hepatitis B.

 Materials and Methods: A summary of epidemiology, natural course and treatment options of chronic hepatitis B is presented in this paper according to AASLD practical guidelines for treatment of hepatitis B (2009). On the basis of serum HBV DNA, alanin aminotransferase and HBe Ag level as well as the liver histological findings the natural course of chronic hepatitis B is divided into four phases: immune tolerance, immune clearance, inactive carrier state and relapse. These phases indicate the patient's immune system activation against the virus and the leading histological liver damage.

 Results: Patients in immune tolerance and inactive carrier state phases do not need treatment and should only be followed up while those in immune clearance and relapse phases do need treatment. Selection of PEG IFN or nucleoside analogues should be based on the presence of cirrhosis, viral load and genotype, drug resistance and also the patient's preference. Drug intolerance or resistance can lead to relapse and drug should be stopped or changed in these occasions.

 Conclusion: Due to the rapid increase of information about chronic hepatitis B treatment and generation of new antiviral medicines, the guidelines for treatment are changing rapidly. Appropriate early treatment decreases mortality and morbidity rate caused by liver disease.