The combined treatment of pegylated interferon and ribavirin in patients with chronic hepatitis C has a lot of adverse reactions. The authors made retrospective studies concerning these estimated adverse reactions. Between the years of 2003 and 2006 138 patients were treated 154 times. The average age of patients was 48 years. Dermatological adverse reactions caused by the treatment were observed in altogether 81 cases (53%). The most common adverse events were alopecia, dermatitis, pruritus, dry skin, injection-site reaction, eczema and reactivation of psoriasis. Dermatological adverse reactions during the treatment are frequent, most of them are treatable, reversible. Occasionally dose modification or the discontinuation of the therapy can also be considered.