Age-related olfactory dysfunction, or presbyosmia, is a common sensory impairment in aging adults. Like other sensory systems, olfactory function deteriorates with age. The incidence of olfactory dysfunction increases at the age of 60 and older and males are more affected than females. Moreover, smoking, heavy alcohol use, sino-nasal diseases, and Down's syndrome are associated with an increased incidence of olfactory dysfunction. Since the decrease in olfactory function is usually gradual, it often goes undetected. The high rate of anosmia over the age of 70 may be due to several factors such as reduced mucus secretion, hormonal changes, changes in epithelial thickness, as well as the reduced neuroregeneration rate in olfactory receptor cells themselves.