Postoperative ileus (POI) is a frequent complication in surgery, particularly visceral surgery. It prolongs the time required for patients to resume their normal diet and their hospitalisation time, placing a heavy burden on the patients, their family and society. One possible solution is vagus nerve stimulation. It both increases motility in the stomach and intestines, and decreases gut inflammation via a7nAch receptors, facilitating the recovery of gut functions. Currently, there is a lack of effective ways to treat POI clinically, and vagus nerve stimulation in clinical trials is usually invasive. Therefore, we aim to develop a device to stimulate the transcutaneous auricular vagus nerve in a non-invasive way to treat POI.