Gastrointestinal motility disorders are a significant health problem accounting for millions of physician visits each year. In many patients, measurement of gastrointestinal transit can provide important diagnostic information. However, current transit measurement techniques involve radiation and cannot make the long-duration, highly detailed recordings needed to fully evaluate patients. The goal of this project is the development of a new technique for outpatient measurement of gastrointestinal transit in patients with motility disorders. The technique captures the fine details of gastrointestinal transit, does not involve radiation, and is capable of making recordings for extended periods while patients undergo their daily routines. In Phase I of this project, a prototype of the Gastrointestinal Transit Measurement System (GTMS) will be constructed and tested in the laboratory. Testing will concentrate on determining the accuracy of the capsule tracking system and the ability of the system to capture transient movements. In Phase II, clinical demonstration testing will be conducted on volunteer subjects with normal and abnormal gastrointestinal function.