 This is a pilot study, and as such is not necessarily expected to achieve statistical significance. A control group will not be used, again owing to the pilot nature of the study. Previous studies have demonstrated the safety of oral bethanechol. It has shown some efficacy in the treatment of gastroesophageal reflux in both adults and children1-8, and there is extensive preclinical data suggesting a beneficial effect for patients with IEM9-14. A single study15 of oral bethanechol in patients with IEM demonstrated a significant improvement in distal esophageal muscle contraction and bolus transit. This study, however measured esophageal function using an inferior method of manometry. The proposed study uses high-resolution manometry to measure the effects of oral bethanechol in patients with IEM, and will yield improved understanding of changes in esophageal function in real-time. The study intervention oral bethanechol will be a single-dose event applied in two encounters, not an ongoing treatment intervention. 