We describe the use of bicyclic carbohydrates for the treatment of hepatitis C virus infections. Different bicyclic carbohydrates were tested in vitro against DNA-viruses, retro-viruses and Flaviviridae sp., an important family of human and animal RNA pathogens. Significant activity was observed against the bovine viral diarrhea virus (BVDV). As pestiviruses, such as BVDV, share many similarities with hepatitis C virus (HCV), the bicyclic carbohydrates in general and the preferred bicyclic carbohydrates more specifically are expected to be a treatment for hepatitis C viral infections.