The SmartPill GI Monitoring System offers an alternative non-invasive method for characterizing disorders of the stomach. The system consists of an ingestible capsule that houses sensors for pH, temperature, and pressure, a receiver for receiving and storing signals from the capsule, and software for displaying data on a personal computer. The capsule samples at regular intervals and transmits the sensed pH, pressure, and temperature data to a portable receiver worn by the subject. After test completion, the recorded data is downloaded to a personal computer for subsequent evaluation. This trial is for subjects 65 years of age and older.