The glycosphingolipid (GSL) compositions of the human, rabbit, and rat gastric mucosa were studied and compared. In neutral GSLs, although GalCer was the most abundant component in every tissue examined, species-specific differences were clearly observed in their composition. Acidic GSLs were composed of sulfatides and gangliosides. Every gastric mucosa contained sulfatides (GalCer-sulfate) in a high concentration. The concentrations of sulfatides per gram of dry weight were 416.0, 933.8, 394.0, 365.9, and 135.9 nmol for the human fundus, human antrum, rabbit fundus, rabbit antrum, and rat glandular stomach, respectively. On the other hand, gangliosides were less in these tissues. The molar ratios of sulfatides to GM3, a major ganglioside, were 4.3, 6.7, 11.1, 2.1, and 1.2 for each gastric mucosa described above, respectively. A high sulfatide concentration in animal gastric mucosa, with its structural similarity to sucralfate, implies that sulfatides may play an important role for gastrointestinal mucosal protection.