© 2017 American Chemical Society. Three sulfur-containing compounds, kujounins A1 (1) and A2 (2) and allium sulfoxide A1 (3), were isolated from the acetone extract of Allium fistulosum â€Kujou'. Their chemical structures were elucidated on the basis of physicochemical evidence, including X-ray crystallographic data. Compounds 1 and 2 possess three rings and an acetal structure and were obtained as complex compounds having disulfide and monosaccharide moieties. On the other hand, compound 3 has a thiolane skeleton derived from allicin. Naturally occurring compounds 1-3 have rare molecular skeletons. This study is the first to determine the absolute configuration of thiolane-type compounds.