The sense of smell is one of the most complex human senses. The receptive zone of the olfactory system is inside the nose. The actual sense of smell, which can be strongly linked to emotions, memories and hedonic judgments, then arises in rather unspecific cortical brain centers. In this area, both the chemosensory analysis of the breath and the retronasal analysis of food aromas are carried out. Odor substances are recognized based on chemical structural features. Most often, intense experiences with the smell in a particular place and events associated with the smell play a role in memory. The evaluation of an odor takes place before the actual odor detection. This is often done using the visual system, picturing the place and remembering an atmosphere that we smell (e.g. “Christmas”).