Abstract: Devices are described which can be used to study the physiological function of the intestinal wall. These devices include an ultrasonic transducer that can be attached to a region of the intestinal wall. The transducer interrogates the wall and echoes are obtained from the different wall layers. The echoes are processed to produce an M-mode display of the wall. This allows monitoring how the wall changes with time. For example, as the wall contracts the muscle layer thickens and this action may be observed with the device. Other sensors and electrodes can be combined with this probe to correlate various physiological action. Finally, several such probes can be combined into a common introducible probe but which will monitor several regions along the intestinal wall. The major advantage of the disclosed device is that it provides a measurement of intestinal motility previously unattainable and it is introducible by endoscopy. This makes it a suitable tool for studying patient disease.