Introduction : Constipation is a frequent problem in the ge­neral population; it could be a functional dysfunction or a symptom of a serious medical condition.

Objective : The aim of the study was to assess the commonest causes and symptoms of chronic constipation in Polish children and adolescents.

Materials and methods : A total of 137 patients (72 boys and 65 girls) with chronic constipation were included. Every patient underwent careful physical examination. Based on the obtained information a specially designed questionnaire was completed. All results were analysed statistically.

Results : Functional constipation was the commonest cause of chronic constipation diagnosed in 126 (92%) children. Less commonly, Hirschsprung’s disease (6 patients – 4.4%), hypothyroidism (4 patients – 2.9%) or a consequence of surgery for anal atresia (1 patient – 0.7%) was found to be a cause of constipation. In all children with Hirschsprung’s disease the symptoms appeared before the end of the 6th month of their life, which was significantly earlier than in patients with functional constipation. The most common concomitant disorders were other gastrointestinal diseases, including food allergy, irritable bowel syndrome, lactose intolerance and problems with intestinal absorption.

Conclusions : The most common cause of chronic constipation in children is functional constipation. It seems that food allergy may predispose children to chronic constipation. Symptoms of Hirschsprung’s disease occur early, most commonly before the age of 6 months.