The present invention relates to the human cellular protein glutathione peroxidase-gastrointestinal as a target for medical intervention against Hepatitis C virus (HCV) infections. Furthermore, the present invention relates to a method for the detection of compounds useful for prophylaxis and/or treatment of Hepatitis C virus infections and a method for detecting Hepatitis C virus infections in an individual or in cells. Also compositions, compounds, nucleic acid molecules (such as aptamers), mono- or polyclonal antibodies are disclosed which are effective for the treatment of HCV infections, and methods for prophylaxis and/or treatment of Hepatitis C virus infections or for the regulation of Hepatitis C virus production are disclosed.