Provided is a composition stably containing a sulfur amino acid, which is derived from an Allium plant, at a high concentration. A method for producing a sulfur amino acid-containing composition, said method comprising: a step for heating an Allium plant a step for treating the heated Allium plant with a gamma-glutamyl bond cleaving enzyme and a step for subjecting the enzyme-treated product to ion exchange chromatography.本發明提供一種穩定且高濃度地含有蔥屬植物之含硫胺基酸的組成物。本發明之含有含硫胺基酸之組成物之製造方法包括以下步驟:對蔥屬植物進行加熱之步驟;以γ-麩胺醯基鍵結裂解酶對該經加熱之蔥屬植物進行處理之步驟;及將該酶處理物供給至離子交換層析法之步驟。