Described herein is a method employing acoustic data from a patient's abdominal cavity to predict potential onset of postoperative ileus (POI) in patients recovering from surgery. According to one embodiment of the method, the rate of intestinal motility events, as well as the change in the rate across specific time periods, is analyzed to predict, or rule out, potential onset of POI. The current risk assessment may then be reported, and used to determine a course of treatment, such as rapidly advancing diet in low risk patients according to enhanced recovery after surgery protocols. The method can be applied at the patient's bedside by a nurse or other medical provider, and used to determine the POI risk assessment for the patient.