The aim of chronic hepatitis B therapy is to suppress hepatitis B virus replication, to control disease activity and progression towards cirrhosis. The first-line drug is the pegylated interferon a, which suppresses HBV replication in 40% of cases, albeit burdened with several contraindications and side effects. Lamivudine, a nucleoside analog inhibiting HBV reverse transcriptase, is indicated in case of failure or contraindication to interferon, may however lead to the selection of resistant mutant HBV strains (20% yearly). In that case, adefovir is indicated and has a lower risk of selection of resistant strains (5% yearly). More effective drugs (telbivudine and entecavir) will soon be available in Switzerland. Two inhibitors of HIV (tenofovir and emtricitabine) may also be used to treat hepatitis B in selected cases. Drug combinations, although supported by theoretical considerations, bring no known clinical benefit and are not reimbursed.