Summary. In this randomized controlled study, we evaluated the efficacy and safety of interferon-α combined with ketoprofen to that of interferon-α alone in naïve patients with chronic hepatitis C. Forty patients were randomized to receive Interferon-α2a (3 million units three times a week) and ketoprofen (150 mg twice a day) and 40 to receive only interferon-α2a at the same dose. Patients were treated for 6 months and followed up for 6 months. Response was defined by undetectable HCV-RNA in serum at the end-of-treatment and after 6 months from the completion of therapy (long term response). At the end of treatment the response was similar in the two group. However, combination treatment showed significantly higher efficacy than monotherapy in achieving long term response (10%vs 32.5%; P = 0.014). Overall adverse events were similar in the two groups. ‘Flu-like syndrome was significantly less common in the ketoprofen plus interferon group which experienced a significantly higher incidence of epigastric pain'. Our results indicate that the combination of ketoprofen plus interferon is significantly more effective than interferon alone in the tratment of naïve patients with chronic hepatitis C and is well tolerated. However this combined treatment appears to be less effective than the association of pegylated IFN and ribavirin which represent the current standard treatment. Thus, the role of ketoprofen in the treatment of chronic hepatitis C needs to be further evaluated against such a treatment.