Compound B₁ (tentative name), isolated from Tetragonia tetragonoides as a principle with anti-ulcerogenic activity, was determined to be a mixture of geometrical isomers of 1-O-β-D-glucopyranosyl-2-N-2'-hydroxypalmitoyl-sphinga-4, 8-dienine on the basis of chemical and spectral evidence. By repeated chromatography, compound B₁ was separated into compounds B_1-a (major) and B_1-b (minor), which were found to be the 4-trans-8-trans and 4-trans-8-cis isomers, respectively. Several cerebrosides and glycolipids from various biological sources were examined for protective activity against the ulcer formation in mice under restraint and water immersion condition.