The purpose of the study was to evaluate interrelations between clinical manifestations of irritated bowel syndrome (IBS) and vegetative dysfunction (VD). The subjects were 153 patients with gastroduodenal pathology: 120--with IBS, and 23--with inflammatory bowel diseases (IBD). The study found that vegetative dysfunction was associated with IBS more often than with IBD. Clinical manifestations of IBS were associated with VD syndrome (VDS), including high intensivity and frequency of abdominal pain, feeling of abdominal swelling, elevated anxiety level, and low rectal sensitivity threshold. VDS is probably one of the links of its pathogenesis. VDS is not associated with a type of intestinal passage disorder. VDS in IBS patients is often of constitutional character and is associated with lower life quality.