Immunoreactive oxytocin (OXT) detected in extracts of human coeliac ganglia and nn. vagi was characterized by high-performance liquid chromatography (HPLC). HPLC/RIA examinations demonstrated that a major part of the immunoreactive material in both investigated areas co-eluted with a reference synthetic OXT, but in the extracts of coeliac ganglia a second immunoreactive peak was also observed.