Use of a compound capable of modulating the level of activity of the OAS gene and/or activity of the OAS protein, in the manufacture of a medicament for the treatment of a patient with or at risk of hepatitis C infection, wherein the compound is not an interferon or an isoprenoid, such as geranylgeranylacetone (GGA). A method of screening for compounds for treating HCV infection, wherein a cell is treated with a test compound and any change in OAS gene activity and/or OAS protein activity or level is assessed, wherein the compound is not an interferon or an isoprenoid, such as geranylgeranylacetone (GGA). Use of a compound capable of modulating the level of activity of the RNAse L gene and/or activity of the RNAse L protein, in the manufacture of a medicament for the treatment of a patient with or at risk of hepatitis C infection, wherein the compound is not an interferon or an isoprenoid, such as geranylgeranylacetone (GGA). A method of screening for compounds for treating HCV infection, wherein a cell is treated with a test compound and any change in RNAse L gene activity and/or RNAse L protein activity or level is assessed, wherein the compound is not an interferon or an isoprenoid, such as geranylgeranylacetone (GGA).