title: Frequency of "functional" gastrointestinal disorders.
mesh_terms: D003109:Colonic Diseases, Functional / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007787:Lactose Intolerance / Q000150:complications; D008297:Male