The characteristics and the prevalence of functional bowel disorders in the general French population are unknown. Based on an epidemiological inquiry in a random population of 1,200 persons who were not seeking care, residents in our country we established: the prevalence of symptoms suggestive of functional bowel disorders; the epidemiological differences between symptomatic subgroups which included abdominal pain with or without bowel dysfunction, diarrhea and constipation. The amount of cases and the prevalence in each subgroup were: abdominal pain, 165, 13.8 p. 100, painless constipation, 75, 6.3 p. 100, diarrhea, 10, 0.8 p. 100. As a whole, functional bowel disorders occurred in 20 p. 100 of our population. The "irritable bowel syndrome" group defined as abdominal pain and/or diarrhea differ from normal subjects by the following higher frequency of age under 50, subjects in active duty, antecedents of diverticulosis, influence of stress on symptoms, nausea, vomiting, migraines, pyrosis and number of visits to a doctor. However neither the sex-ratio nor professional occupation were relevant. The constipation group differed from normal because of the higher frequency of female sex, antecedents of hiatus hernia, use of laxatives but not because of age nor by the number of associated symptoms. In conclusion, functional bowel disorders occurred in 20 p. 100 of our population; two subgroups were clearly different from an epidemiological point of view, the irritable bowel syndrome (13 p. 100) and constipation (7 p. 100); therefore these two groups deserve a specific physiopathological, psychological and therapeutic approach.