Psychopathology in severely anorexic patients often seems to be of compulsive and delusional quality rendering therapeutic approaches extremely difficult. With conventional therapeutic regimes failing, administration of the novel antipsychotic olanzapine induced remarkable improvement in five cases reported here. Paranoid ideation concerning body image or weight gain decreased and sedative effects helped to reduce inner tensions and phobia with respect to food intake. Olanzapine, therefore, might represent an important therapeutic tool in anorexic patients who present the following characteristics: long-term history of anorexia nervosa mostly with several hospitalisations, missing perception of their severe state of illness, refusal of therapy, delusional quality of anorexic thinking, risk of discontinuation of therapy with life-threatening consequences.