Reusable thermal pack and flow retardant gel for use therein

A thermal pack used for therapeutic hot and cold treatment, comprising:

• a. a first flexible permanently sealed bag having at least one chamber;
• b. a semi-rigid, non-flowing, viscous gel comprising a colloidal dispersion of a solid with a liquid and being sealed in said first bag, said gel being capable of retaining heat or cold, and said gel comprising a mixture of materials including clay, a liquid and a fibrous material, said clay being a clay substrate in an amount of from about 15% to 30% by weight, the liquid including glycol and water wherein the water is in an amount of from about 0% to 75% by weight, and said fibrous material being of sufficient concentration to impart a negligible flow rate in said gel and to provide uniform contact between the thermal pack with an affected area, wherein said sufficient concentration is about 1% to 10% by weight;
• c. a second flexible sealed bag containing at least one open chamber which can be inflated, said second bag being disposed adjacent and coextensive with said first bag and being connected thereto;
• and
• d. a means for inflating and sealing said second flexible sealed bag.