In the first group, 24 highland Swiss Etivaz cheeses manufactured using an open fire with logs, and 25 Swiss Gruyère cheeses manufactured in a steaam heated vat as reference were analysed for their polycyclic aromatic hydrocarbons (PAH) content. In the highland cheese, anthracene was present specifically , fluoranthene, fluorene and naphtalene were found only occasionally. All these compounds are related to the prcessing technology. Phenanthrene and pyrene were found in a higher concentration in the highland cheese than in the refernce cheese, thus indicating that the latter compounds originated both from the the environment and the smoke of fire. In conclusion, these 6 various components may be considered as tracers for highland cheese with a Protected Designation of Origin (PDO). In a second group, 4 Swiss and 14 foreign cheeses, 9 with and 9 without (as reference) smoke flavour, were also analysed for their PAH content. In most cheeses treated with warm smoke the same PAH occured in a much higher concentration than in the previous highland cheeses. Moreover, several other PAH have been found such as benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene. Benzo(a)anthracene which is present in trace in all cheeses analysed seems to be a polluant, and should not be related to the smoking procedure. The presence of the latter compounds which are generally considered as carcinogenic substances is discussed in terms a toxicology as well as smoking technology. The analytical data measured are compared with the values published in the literature. The liquide smokes analysed (n=3) do not contain any PAH but are nevertheless highly efficient flavouring preparations. They may be recommended as a vuluable alternative procedure considering their low risks for the human health in comparison with a too intensive technology using a warm smoke