Cell surface carbohydrates are excellent markers for cellular differentiation and maturation due to great structural and antigenic diversity and to known precursor/product relations. Several blood group related carbohydrate antigens were analyzed in human labial stratified non-keratinized epithelium from 16 healthy individuals by immunohistology using monoclonal antibodies. The expression of these antigens was correlated with erythrocyte phenotype and saliva secretor status. Three distinct compartments of the epithelium were found and defined by the sequential expression of derivatives of Type 2 chain structures: lower, confined to basal cell layers (N-acetyllactosamine), middle, to parabasal cell layers (H) and upper, to spinous cell layers (Le(y)/Le(x)). Although the antigens are related to blood group antigens they are largely expressed independently of the ABO, Lewis and secretor types, and may therefore serve as "universal" markers in differentiation studies of normal and pathological epithelium.