Background. Numerous experimental findings have underlined the relationships between liver damage and production of oxygen-derived free radicals during inflammation. In chronic hepatitis C liver disease this damage may be attributed to altered oxide-reductive balance and glutathione (GSH) depletion, Moreover, it may be linked to chronic inflammation provoked by the replicative activity of the hepatitis C virus and its relationships with immune system cells. Our aim was to assess the effects of combined IFN+NAC treatment to compare the effects of interferon alpha - n1 associated with N-acetyl cysteine treatment with the results observed using interferon therapy alone. Methods. Experimental design: prospective randomised study, Setting: ambulatory and hospitalised rare. Patients: 77 selected patients affected by chronic C hepatitis. Interventions: our patients were investigated by laboratory tests (ALT values, RIBA test, HCV-RNA, oxide-reductive balance), liver biopsy and liver US. The recruited subjects were treated with interferon and N-acetyl cysteine or with interferon alone. Results, Our findings confirmed the presence of oxidative stress in patients with chronic hepatitis C and showed earlier relapse in patients treated with interferon alone. The difference between the results in patients treated with interferon and N-acetyl cysteine and those on interferon alone was significant. Conclusions. The good results and absence of side effects in patients treated with interferon + N-acetyl cysteine recommend wider use of this association.