A system for the detection and analysis of at least one volatile substance in breath samples of a subject, including at least one source of infrared radiation adapted to the wavelength range of specific absorption peaks of said substances, a plurality of reflecting surfaces of said radiation adapted for collimation onto at least one detector providing a plurality of electrical output signals corresponding to the transmission of said radiation within wavelength intervals corresponding to said absorption peaks, at least one measuring cell including a mechanical support structure defining the position of said source, reflecting surfaces and detector, adapted to the reception and disposal of said breath sample, and exposing it to said radiation, at least one electronic signal processing unit with capacity to analyse said signals with respect to pre-programmed information concerning infrared absorption spectra of said substances. The response of the system being displayed or otherwise communicated, and perceived as essentially instantaneous.
