Olfactory disorders are common in the general population, but research into the consequences of these disorders has been lacking. Not until recently, when specific tools for assessing changes in quality of life due to olfactory disorders have become available, have systematic investigations been conducted. In this article we present the most important roles that olfaction plays in humans and review the scientific literature on the consequences of olfactory disorders. This review suggests that quality of life, regarding safety issues and interpersonal relations, as well as eating habits and nutritional intake are severely altered in a large proportion of patients with olfactory disorders.