Abstract: A medical diagnostic device for analyzing gases in expired breath. The device includes a spectroscopic analyzer component for obtaining a patient's breath concentration profile; a computer operably coupled to the analyzer component; a memory component operably coupled to the computer; and a database stored within the memory component containing spectroscopic breath analysis profiles. Each profile is characteristic of at least one of a plurality of medical conditions. A computer program compares the obtained patient's breath profile to the stored database of spectroscopic breath profiles, such that diagnosis of the presence or absence of a medical condition is facilitated.