Provided are methods and compositions for treating hepatitis virus infections in mammals, especially humans. The methods comprise (1) administering N-substituted-1,5-dideoxy-1,5-imino-D-glucitol compounds in combination with nucleoside antiviral agents, nucleotide antiviral agents, mixtures thereof, or immunomodulating/immunostimulating agents, or (2) administering N-substituted-1,5-dideoxy-1,5-imino-D-glucitol compounds in combination with nucleoside antiviral agents, nucleotide antiviral agents, or mixtures thereof, and immunomodulating/immunostimulating agents.