A hydrogen-generating substance that reacts with moisture (liquid water or water vapor) in a medical substance or moisture in air introduced into a medical container is kneaded into an exterior sheet 40 of the medical container that encloses the medical substance therein. The medical container can be a bag-shaped medical container, a tube-shaped medical container, a medical container with a sealing fastener or the like. The medical substance containing moisture can be blood, an injection solution, a drug solution, a nutrient solution, a replenishment solution (an infusion solution), an instillation solution or the like. A solid preparation is preferably enclosed within the medical container with the sealing fastener. For example, the hydrogen-generating substance to be kneaded can be metal magnesium and is preferably fine-powdered ceramics obtained by firing the mixture of a hydrogen-generating substance and a mineral substance such as calcium.
