The authors report an unusual case of a driver who tested positive for alcohol proven by a breathalyzer during a random police road test. An initial hypothesis of auto-brewery syndrome was put forward, following a clinical exposure test and blood sample examination by a non-specific enzymatic method. However, this was later excluded by conducting a specialized glucose testing and examination of blood samples by gas chromatography in a forensic department. Because the number of such cases is insufficiently reported in the medico-legal literature, this case report and concise review of the literature delivers useful information necessary for a correct and professional approach, with a detailed proposal on how to definitively resolve this obscure problem of forensic alcohology.