Inclusion criteria were cases that developed interstitial pneumonitis in the setting of HCV treatment, written in English, French or German. Exclusion criteria were other pulmonary diseases, e.g., sarcoidosis, exacerbation of asthma, BOOP, acute respiratory distress syndrome (ARDS), infectious pneumonia, liver transplanted patients, HIV co-infected patients, and interferon beta treatment. Patients who developed interstitial pneumonitis during interferon therapy with a disease other then hepatitis C were also excluded. The references of the traced articles were scrutinized for additional articles.