The invention provides a composition comprising an inhibitor of Na+-taurocholate cotransporting polypeptide (NTCP) and an active ingredient selected from the group consisting of a nucleoside analogue such as lamivudine, telbivudine, or entecavir, a nucleotide analogue such as tenofovir, adefovir and an immunomodulator such as interferon alpha. The NTCP inhibitor inhibits HBV/HDV entry into a cell and is preferably derived from an HBV pre-S1 peptide. Also provided are methods of treating HBV and HDV infection, hepatitis B and D, or chronic hepatitis B and D.