Parosmia troposmia (Gk.) or cacosmia, (Gk.) is an olfactory dysfunction that is characterized by the inability of the brain to properly identify an odor’s “natural” smell.hat happens instead, is that the natural odor is transcribed into what is most often described as an unpleasant aroma, typically a “‘burned,’ ‘rotting,’ ‘fecal,’ or ‘chemical’ smell.” There are instances, however, of pleasant odors.