Biopsy specimens from histologically normal human gastric mucosa were examined histochemically with the use of lectins. Significant differences were found in the glycoconjugate patterns of the surface mucous cells between the body and the corresponding antrum. Two lectins (Ulex europaeus agglutinin I and Ricinus communis agglutinin I) specific for fucose and galactose residues stained the apical membrane and the intracellular (perinuclear) region of the antral mucosa more strongly than those of the body (P < 0.04). Body and antral biopsies from patients with Helicobacter pylori-positive chronic active gastritis were also studied, but the lectin patterns of Helicobacter pylori-infected body and antrum did not differ. On comparing these chronically infected gastric biopsies with normal antral mucosa, however, significant changes could be seen with the fucose-binding lectin as well as with two other lectins (succinylated concanavalin A and peanut agglutinin). These differences could have been induced directly by bacterial virulence factors or could be due to non-specific reactions to the inflammatory process.