On May 20, 2026, Japan's Ministry of Health, Labour and Welfare (MHLW) issued notifications reinforcing existing safety requirements for hair cosmetics containing henna and henna-derived substances, following a consumer safety alert concerning severe allergic reactions associated with certain henna hair products.

The action was prompted by a report released by the National Consumer Affairs Center of Japan (NCAC), which documented cases of anaphylaxis linked to henna products containing oxidation dyes. According to the investigation, some affected products lacked adequate precautionary information regarding allergy risks and patch testing on their packaging.

In response, MHLW instructed prefectural and municipal health authorities to disseminate the existing henna-related safety requirements to cosmetic businesses and relevant industry organizations under their jurisdiction. The measure aims to strengthen consumer awareness of potential allergic reactions and improve compliance with labeling requirements.