Immunosuppressive drugs can cause serious side effects. We describe a case of a young patient with ulcerative colitis (UC), in whom after azathioprine treatment acute pancreatitis occurred. Then for a period of four months tioguanine and briefly cyclosporine A (5 days) were given; these caused pancytopenia, infectious mononucleosis, and herpetiform dermatitis. Along with side effects, mood disorder as an anxiety-depressive syndrome was present. Return to classical mesalazine therapy combined with tianeptine gave a few months of remission of UC and mental status improvement.