Attempts have been made to develop a procedure for preserving and analysing the surface mucous layer of the human stomach in paraffin sections. Histologically normal gastric mucosae were obtained from 20 surgically removed stomachs. Of the different fixatives tested, Carnoy's solution gave rise to the most satisfactory results. In Haematoxylin-Eosin stained sections, the surface mucous layer appeared as a thick eosinophilic layer coating the gastric mucosal surface and measured 55.4 +/- 2.5 microns in the fundus and 21.8 +/- 1.0 microns in the pylorus respectively. A dual staining method consisting of galactose oxidase-cold thionine Schiff and paradoxical concanavalin A staining was applied to the surface mucous layer in order to reveal the distribution pattern of mucins secreted by two types of mucous cell in the gastric mucosa: surface mucous cells and gland mucous cells. As a result of this staining, an alternating laminated layer was visualized which consisted of the particular two types of mucin. In five cases, the surface mucous layer was examined in unfixed frozen sections. This layer was only partially preserved but revealed the same laminated structure. These results indicated that gland mucous cell mucins contribute to form the surface mucous layer.