In contrast to what the medical community thought, human olfaction is far more functional and performing than previously believed. Almost fifteen percent of the general population is concerned by an olfactory disorder. The causes of olfactory dysfunction are numerous and in certain cases olfactory alteration precedes neurodegenerative or systemic diseases. Thus, a thorough workup consisting of an otolaryngological examination, olfactory testing and if necessary further exams is emphasized. Since medical knowledge on olfactory dysfunction is only emerging, curative treatments are not always available. In contrast to other neurons, olfactory neurons have the capacity of spontaneous regeneration and a large part of the physician's job is to inform and follow-up patients with olfactory disorders.