Autonomic nervous system has been considered to play an important role in the mechanism of nasal allergic symptoms such as rhinorrhea and nasal obstruction. The constriction and dilatation of blood vessels in nasal mucosa are mainly controlled by sympathetic tone and nasal obstruction can occur as a result of dilatation of blood vessels in nasal mucosa. The purpose of this study is to investigate the distribution of catecholamines in normal nasal nucosa by using SPG(sucrose-potassium phosphate-glyoxylic acid) staining method and compare the degree of distribution of catecholamines between the patients with perennial allergic rhinitis and normal subjects. The results are as follows. 1) In normal nasal mucosa, catecholaminergic fluorescence was noted in venules and cavernous sinusoids and was not noted in arterioles. 2) In the epithelium and the glands of normal nasal mucosa, catecholaminergic fluorescence was not noted. 3) Catecholaminergic fluorescence was significantly decreased in venules and cavernous sinusoids of allergic nasal mucosa than in those of normal nasal mucosa. From above results, the loss of Catecholamines in venules and cavernous sinusoids may be one of the important disease processes responsible for the nasal obstruction in patients with perennial allergic rhinitis.