This application discloses a system for detecting mouth alcohol which is integrated with a breath-measuring instrument. In an embodiment, the breath-measuring instrument comprises a single fuel cell system, wherein the single fuel cell measures an individual's alveolar breath as well as detection of any mouth alcohol. In a further embodiment, the breath-measuring instrument comprises a first fuel cell and a second fuel cell, wherein the first fuel cell measures alveolar breath and the second fuel cell detects mouth alcohol.
