Initial analysis yielded a total of 291 articles. The abstracts of this set of articles were scrutinized for cases that developed (interstitial) pneumonitis in the setting of HCV treatment. Subsequently data were retrieved with special attention to the following items: demographics (ethnicity, gender, and age), dosage and type of (peg)interferon, concomitant use of ribavirin (dosage), symptoms, interstitial pneumonitis, onset, symptoms, and outcome on follow-up.