Summary. Incomplete suppression of hepatitis C virus (HCV) replication with persistence of minimal viremia (partial virologic response) leading to treatment failure can be observed in a significant proportion of HCV type 1-infected patients during antiviral therapy. Recently, high-dose intravenous silibinin has demonstrated strong antiviral activity against HCV. We were therefore interested in whether patients with partial virologic response can be rescued by the on-treatment addition of a short-term course of high-dose intravenous silibinin infusions. Twenty patients who failed to achieve a complete virologic response to different interferon-based regimens qualified for the rescue strategy and received 1400 mg/day silibinin infusions on two consecutive days. Complete viral suppression (below the limit of detection <6 IU/mL, TMA assay) could be induced in 13 of 20 patients within the first week after the short-term silibinin infusion, and all but one of them also remained HCV RNA negative during the subsequent follow-up period on continued peginterferon plus ribavirin treatment. In the remaining seven patients, no complete suppression could be achieved although four showed a significant HCV RNA reduction in response to silibinin. Silibinin infusions were generally well tolerated, and activation of abdominal peristalsis with nausea, diarrhoea and vomiting were the most prominent side effects. Of the twelve patients who exhibited a durable response to peginterferon and ribavirin treatment, three achieved an SVR, two achieved a week 12 SVR and four suffered a viral relapse. Three patients could not complete the assigned antiviral treatment with peginterferon alpha and ribavirin for nonvirological reasons. Short-term administration of high-dose intravenous silibinin might be an interesting approach to rescue patients with ongoing minimal residual viremia while on interferon-based therapy. These preliminary findings may stimulate further studies to evaluate more refined therapeutic strategies.