[The e-cigarette: a toxicological box of Pandora].

It is argued by the author that the addition of flavorings to e-cigarette devices presents a major uncertainty in the health risks of these nicotine delivery-systems. These flavorings have usually been tested only for oral uptake situations and not for e-cigarette devices in which unkown and possible hazardous combustion products can be formed. A similar uncertainty exist for the de novo formation of combustion products of humectants. Experimental studies have already indicated the possibility of adverse effects on the respiratory system. The now observed lung symptoms with e-cigarette users are there not unexpected from a toxicological point of view. The overall complexity of the mixture of combustion products clearly hampers an adequate toxicological risk assessment, which is further increased by the large variety of liquids and delivery devices on the market. The use if e-cigarette devices may very well be a toxicological box of Pandora.