Lactobacillus acidophilus is known to have an inhibitory activity on growth of Helicobacter pylori and this activity has been attributed to lactic acid and antibacterial agents produced by Lactobacillus. Since every Lactobacilli produces lactic acid, an another factor must exist for L. acidophilus to inhibit H. pylori growth. In this work, the inhibitory activity of L. acidophilus on H. pylori adherence was studied. An immunoabsorbent assay using TLC plate was developed and used for screening the inhibitory activity of various Lactobacilli on H. pylori adherence. Glycolipid, the attachment site for H. pylori, was isolated from blood type O red blood cells and spotted on a TLC plate. The H. pylori adherence increased linearly with increasing amounts of glycolipid spotted on the TLC plate. Various L. acidophilus strains, but not L. casei, appeared to inhibit H. pylori adherence to glycolipid, and the adherence decreased linearly as the concentration of the Lactobacillus increased. The results show that the inhibitory activity of L. acidophilus on H. pylori adherence is an another factor for L. acidophilus to inhibit H. pylori growth.