Aim. The aim of this study was to evaluate diet of patients with IBD, their nutritional status and potential differences as compared to diet of healthy persons.Material and methods. The examination included the patients of Internal, Metabolic Diseases and Dietetics Ward and Gastroenterology, Internal Diseases and Human Nutrition Ward of Heliodor Święcicki Clinic in the Poznan University of Medical Sciences in Poznan. The criterion allowing participation into the study involved a diagnosed ulcerative or Crohn’s disease, basing on histopathology and radiological examination. The study was conducted on 50 patients, 25 women and 25 men. The control of group included 50 persons, 30 women and 20 men, potentially healthy and occupationally active. In the study the authors' own questionnaire was used, which contained questions related to diet and evaluating conditions of nutrition, based on the results of anthropometric measurements and selected biochemical parameters.Results. The study documented that IBD affected diet, which proved to be distinct from that of potentially healthy person. Course of the disease reduced some laboratory parameters in serum: decreased levels of total protein were detected in 40% patients, reduced levels of albumin in 28% patients and of haemoglobin in 72% patients with IBD. Most of patients introduced some modifications and dietary restrictions to reduce the symptoms and prolong remission. Presentation of such attitudes, indicates a need for an effective multidirectional education, which should affect a conscious decision making about the diet. The Body Mass Index and evaluation of nutrition demonstrated that IBD predisposed development of malnutrition: as compared to the control group, 28% of the patients manifested underweight.