[Development of the sense of smell, a review]

The pre- and postnatal development of human olfaction is described. Data from animal experiments a partially reviewed as a base for understanding of the results of olfactory testing of babies and children. In rat fetuses the vomero-nasal-organ is used as detector of molecules in the amnion fluid. The perinatal aeration of the nasal cavity allows the adequate stimulation of the olfactory epithelium. The early postnatal olfaction is a brainstem function; later the olfactory cortical area are used for the discrimination between odorants. There are only a few investigations about the olfactory function in childhood, so that the testing of olfaction for detecting abnormal brain developments is just in the beginning.