On May 14, 1991, the former Ministry of Health and Welfare of Japan (now MHLW) issued the Japanese Standards of Quasi-drug Ingredients (JSQI 1991), marking the country’s first unified standard for quasi-drug raw materials. The standard was developed by consolidating Ingredient Specification I (active ingredients) and Ingredient Specification II (additives), which were originally set out in Attachments 2 and 3 of the Standards for Manufacturing (Importing) Approval of Hair Dyes.