In the Ministry of Health, Labour and Welfare Notification No. 112, the purpose of use of alkaline ionized water apparatus (household-use electrolytic water generators) which are household-use medical devices is defined as "generation of alkaline electrolytic water for drinking to improve gastrointestinal problems". ("Improvement of gastrointestinal problems" is the beneficial effect based on the experimental results verified through clinical testing. In clinical testing, stomach problems such as stomach heaviness or discomfort, etc. or intestinal problems such as bowel movement conditions, etc. were the subjects of the testing. An overview of the testing is provided in the research results pages.)
Conventionally, devices certified as medical apparatuses were those which were effective against chronic diarrhea, indigestion, abnormal fermentation in intestines, acid control, and acid indigestion.
On the other hand, since acidic water can be used for applications other than drinking, such as washing faces, washing, etc., it is expected to have an astringent effect.
For alkaline ionized water, activities for reverification of its safety and effectiveness are performed by the Alkaline Ionizer Review Committee established in 1993, and as a result of performing double-blind comparative clinical testing with gastrointestinal problems as the subject (the world's first for drinking water), the conclusion "Alkaline ionized water is effective." was stated.