The knowledge of the mechanisms giving rise to halitosis in the mouth is quite limited despite the social constraints the condition imposes and the attendant commercial interest that results. In part, this understanding is limited by the difficulties inherent in undertaking in vivo studies which are further exacerbated by the complexity of the systems under investigation, in particular, the influence of transport mechanisms such as salivary flow, pH, temperature and others had not been investigated. The research described here is based on a new approach to investigate the transport mechanisms contributing to oral malodour emanating from the tongu, dorsum as the main source of volatile compounds in the mouth (Yaegaki and Sanada 1992, Rosenberg and Leib 1995, De Boever and Loesche 1996).