(1) Ribavirin is licensed for patients with hepatitis C who have not been treated previously or who have relapsed. According to the licence, ribavirin must be combined with interferon alfa-2b. (2) The clinical file is bulky and of acceptable methodological quality. (3) Some trials have shown that ribavirin monotherapy has no effect on viral load. Two trials involving patients who had relapsed after transaminase normalisation on interferon alfa-2b monotherapy show that the ribavirin + interferon alfa-2b combination is more effective than interferon alfa-2b alone in rendering viraemia undetectable and normalising transaminase activity for at least 6 months after treatment cessation. (4) A trial of patients resistant to interferon alfa monotherapy showed that it was more beneficial to combine ribavirin + interferon alfa-2b than to double the dose of interferon alfa-2b alone, in terms of driving viraemia below the detection limit and persistently normalising transaminase activity. (5) Three trials involving patients who had not been treated previously showed that the ribavirin + interferon alfa-2b combination was more effective than interferon alfa-2b monotherapy in driving viraemia below the detection limit for at least 6 months after treatment cessation, and in reducing the liver inflammation score. No effect on fibrosis or on the risk of cirrhosis has yet been demonstrated. (6) The best duration of treatment is not known, but seems to depend on prognostic factors. The following factors might permit shorter treatment: relatively low viral load, early-stage fibrosis, female sex, age below 40 years, and infection by genotype 2 or 3 strains. (7) The ribavirin + interferon alfa-2b combination causes haemolytic anaemia in most patients, and this can be severe. (8) Ribavirin is teratogenic and causes sperm defects.