Immunohistochemical localization and morphology of 5-hydroxytryptamine immunoreactive cells (5-HT cells) in the digestive tract of Neomys fodiens were investigated by using the ABC (avidin-biotin-peroxidase complex)immunostaining technique.The 5-HT positive immunoreactive cells could be observed throughout the intestinal tract,from duodenum to rectum.The cell density curve appeared parabolic,with the highest in the jejunum (4.50±1.60),followed by the duodenum (4.00±1.33),while the lowest in the rectum (1.60±0.94).The 5-HT cells distributed at the bottom of epithelial cells,between epithelial cells,between glandular epithelial cells or in the lamina propria.The 5-HT cells showed two shapes,round and taper.It is suggested that 5-HT positive immunoreactive cells in the digestive tract of N.fodiens should have both endocrine and exocrine functions,and their distributive density is related to its living habit and the way of existence.