A self-heating, self-hydrating pouch to simultaneously heat and hydrate a prepackaged, partially or completely dehydrated food or beverage product that is stored in the pouch. The pouch comprises multiple layers of material that prevent the transmission of water and gasses thereby preventing deterioration of the prepackaged food or beverage product. The pouch includes a membrane filter structure and flameless, exothermic reaction agents. The user adds potable or non-potable water to the pouch. When the water contacts the exothermic reaction agents, an exothermic reaction occurs which heats the water above 200.degree. F. The membrane filter structure filters the heated water to remove bacteria, viruses, chemicals and by-products of the exothermic reaction. The filtered, heated water contacts the partially or completely dehydrated food product or dehydrated beverage product and simultaneously heats and hydrates the food or beverage product.