Introduction. Chronic constipation and his symptomatological aspects, assumes a pathological role of social interest entailing high costs. Pharmacological multidrug therapies are often ineffective. The motility function, immune modulation, enteric sensibility, permeability of the mucosal and the submucosal vascular system, proliferation and activities of the enterochromaffin cells, are subject to autonomous control of the Enteric Nervous System (ENS) and its interrelation with the Central Nervous System (CNS) through the Autonomous Nervous System (ANS). The interaction of this neuronal systems occurs through electrical signals, generated by transmembrane action potentials. Aim of the study. We have conduct a pilot study with clinical observation, to evaluate the effects on regularization of the colon motility, through administration a transcutaneous negative asymmetrical electrical pulse patterns. Materials and methods. We selected 15 patients with chronic constipation (interval between evacuations on average 9 days (6-12), and partial spontaneous evacuations or induced by monodrug or multidrug cholagogues therapy), excluding the presence of organic or inflammatory diseases, outflow disfunction and defecatory disorders. All patients underwent at cycle of 15 FRE.M.S. therapy (F.T.) sessions, at fixed and variable frequency (software controlled). The electric fields, generated by ETS 501 neurostimulator machine (Lorenz Biotech,Italy), has been administered using two methods: on the ascending, transverse and descending colon segments, with fixed frequency (400 Hz, duration μ seconds, amplitude Volts, patient controlled through remote control +/-1Volt); on the sigmoid tract with variable frequency ( Hz, pulse duration μ seconds, amplitude Volts patient controlled through remote control). Results. On all the patients we obtained spontaneous regularization of the bowel habit, daily or tri-weekly (6 cases), bi- weekly (8 cases). On one case a second therapy cycle was necessary to obtain spontaneous tri-weekly evacuations. The follow-up of 12 months, proved that the frequency of evacuation could be maintained for 6-8 months without clinical symptomatology and without cholagogues use. Conclusions. This clinical observation allows us to assume that particular electrical signal patterns at variable frequency, amplitude and duration, may allow produce an electro- physiological interaction with the neuronal systems (so called BGA), which governs the colon functions. On an ensuing protocol we will study which neurohistological and immunohistochemical modifications may be induced by electric fields generated by this type of pulse. Key words: constipation, electric stimulation, enteric nervous system Abbreviations: FRE.M.S., FREquency Modulated neural Stimulation; ENS, enteric nervous system; ANS, autonomous nervous system; CNS, central nervous system; BGA, brain gut axis; Corresponding author Massimo Massari M.D. Catholic University of S. Heart-Columbus Hospital Rome V. G. Moscati 31, Rome Italy Tel/Fax Associazione Cattolica per lo Sviluppo della Ricerca nelle Terapie Riabilitative ONLUS CHRONIC CONSTIPATION: RESULTS OF A CLINICAL OBSERVATION IN THE USE OF FRE.M.S. (FREquency Modulated neural Stimulation) THERAPY. PILOT STUDY. Massari M *°, Zanella A.**, Desideri P.°, Rando G.*, Wiel Marin A.* * Dep.Surgical Sciences, U.O.C. General Surgery 1, Catholic University S. Heart-Columbus Hospital Rome ** Lorenz Biotech, Medolla, Modena Ce.Te.Ri. Rehabilitation Therapy Centres, Onlus, Rome 13° UNITED EUROPEAN GASTROENTEROLOGY WEEK Copenhagen October 2005 UNIVERSITA CATTOLICA DEL SACRO CUORE FACOLTA DI MEDICINA E CHIRURGIA AGOSTINO GEMELLI pelvic muscles basal tone maximal contraction pelvic muscles tone FRE.M.S. therapy application CTT at 24h after marker ingestion CTT control after 5 days risoluzione schermo consigliata 1024 x 768 pixel