The case of a patient ulcerative colitis involving an autoimmune base who was treated with recombinant alpha-2b interferon for presenting chronic active hepatitis in relation to virus C is reported. Such treatment was achieved in addition to improving the hepatic disease normalizing the transaminases control the outbreak of ulcerative colitis that the patient was presenting from some days before beginning the treatment. Various aspects are discussed related to the autoimmunity in the ulcerative colitis and in the chronic C hepatitis and the exarcebation of autoimmune phenomena which may lead to interferon therapeutic. As a basis for the above and the review of the literature, we concluded that the existence of ulcerative colitis does not contraindicate the use of alpha-2b interferon in patient with chronic hepatitis, although special control of the disease should be carried out during the treatment period.