Abstract: A method of applying therapeutic heat a patient including forming a heating pad having an outer container having a first side formed by a material non-pervious to water and a second side formed by a material pervious to water. The container substantially encapsulates an outer bag containing and exothermic chemical and an inner bag containing a solvent. Further, the first side is covered by a layer of heat insulating materially and the second side by a layer of sponge-like material. The fist side and sponge-like material are contacted with water, thereby causing the sponge-like material to absorb water. Then the inner bag is fractured, causing the chemical and solvent to mix, producing heat, which is directed at the sponge-like material. The second side of the heating pad is then placed against the body, causing moist heat to be applied to the body. The pad may by tied to the body using straps extending from the ends of the container.