Intestinal rhythm disorders are very prevalent in today's society and can present in different forms and intensity in people of varying ages. The most common manifestations of a change in intestinal rhythm are constipation, diarrhoea and irritable bowel syndrome (IBS). A thorough clinical history usually enables diagnosis and appropriate, prompt treatment. Constipation involves bowel movements that are infrequent and changes in stool size or consistency. Complementary tests are rarely needed. Diet, establishing bowel habits and laxatives are the basis of maintenance. Diarrhoea that lasts longer than 2 weeks is referred to as chronic. The most frequent causes are: non-specific chronic diarrhoea, adverse reactions to foods, coeliac disease, giardiasis, post-enteritis syndrome and carbohydrate intolerance. IBS is a gastrointestinal disorder characterised by chronic abdominal pain and altered bowel habit of no organic cause.