Endoscopic coagulation of the sphenopalatine artery (SPA) is indicated in patients with recurrent or severe posterior epistaxis. The present work aimed at studying the effects of the sphenopalatine artery coagulation on the nasal seromucinous glands. The study was carried out on 30 patients who were scheduled for endoscopic SPA coagulation. All patients signed informed consents that were approved by the Committee of Medical Ethics. Minute punch biopsies were taken from the inferior turbinates, under local anesthesia, just before the procedure as well as 12 weeks and 1 year postoperatively. The biopsies were stained with hematoxylin and eosin and PAS Alcian blue. Histochemical examination was done for the activity of the succinic dehydrogenase, alkaline phosphatase and cholinesterase enzymes. Morphometric analysis as well as analysis of the histological and histochemical results showed that SPA coagulation was followed by an early decrease in the size, number and secretory activity of the nasal seromucinous glands, which was associated with decreased activity of the alkaline phosphatase enzyme in the endothelial cells of the nasal blood vessels and decreased activity of the cholinesterase enzyme in the cholinergic nerve fibers. These changes, however, were temporary and reversible since examination of the late postoperative biopsies, at 1 year, showed normalization of the number, appearance, and histochemical activity of the glandular acini as well as the surrounding blood vessels and cholinergic nerve fibers.