To provide a method for the treatment of diabetes, senile insomnia, shoulder discomfort, whiplash, gastric ulcer and duodenum ulcer and rejuvenation by drinking water having decreased deuterium content (super-light water).

The method for the treatment of senile insomnia, shoulder discomfort, whiplash, gastric ulcer and duodenum ulcer and rejuvenation comprises the use of water having decreased deuterium content (super-light water) which is an aqueous solution composed of water and 0.1-110 ppm deuterium or 0.1-110 ppm deuterium as an activator in addition to a carrier or an assistant and having the form of pharmacological product or a pharmaceutical solution suitable for human.