An attempt is made to synthesize the fundamental information concerning the pathogenesis of chronic functional digestive disorders, which should be designated as "chronic functional dyspepsia". At present the term "irritable colon" does not seem justified since the disorder affects the entire gastrointestinal tract. In the development of this disorder three types of fundamental pathogenic factors apparently participate: 1. Deficient protein nutrition leading to hypotrophy of the intestinal mucosa. 2. Alterations of intestinal motility related fundamentally to neurotic dysfunction. These are hyperreactive phenomena by the smooth muscle in response to normal stimuli on a background of generalized gastrointestinal hypotonia. They seem to be due to an excess of certain neurotransmitters, principally dopamine, at the level of the myenteric plexus. 3. Infectious factors of the infectious Crohn type provoked by intestinal bacterial overgrowth. These derive from motility alterations, with stasis or delayed transit, and hypotrophy due to deficient nutrition that alters the intraluminal ecological medium. This alteration impairs the development of the normal saprophytic flora and facilitates the proliferation of anaerobic colonic germs, leading to intestinal bacterial overgrowth.