Devices, systems and methods are disclosed for treating or preventing gastroparesis, functional dyspepsia, and other functional gastrointestinal disorders. The devices comprise a housing and an energy source for generating an electric current and transmitting the electric current from the electrode through an interface and the outer skin surface of the patient to a selected nerve fiber within the patient as the interface contacts the outer skin surface. The electric current is sufficient to modulate the selected nerve fiber to at least one of treat or prevent at least one of gastroparesis, functional dyspepsia, or ileus in the patient.