The present invention provides methods for treating a flavivirus infection, including hepatitis C virus (HCV) infection, in an individual suffering from a flavivirus infection. In some embodiments, the methods involve administering to an individual in need thereof an effective amount of an agent that inhibits enzymatic activity of a membrane-bound .alpha.-glucosidase inhibitor. In other embodiments, the methods involve administering to an individual in need thereof effective amounts of an .alpha.-glucosidase inhibitor and at least one additional therapeutic agent.