An improved improved, externally heated thermal pack, has an enclosure or bladder comprised of a skin of a durable flexible film, and has a fill of a blend of propylene glycol (mono- or poly-), water, and a superabsorbent cross-linked polyacrylic salt. The fill is hermetically sealed within the enclosure or bladder. Favorably, the polyacrylic salt and the propylene glycol/water solution are at a ratio in a range of about 21% to 28%. The thermal packs can be in a range of sizes and styles, and exhibit improved stability, better flexibility, smaller risk of failure, reduced risk of scalding or burning the patient, less risk of bacterial contamination and greater service life.
