An experimental study was carried out using rats to evaluate the effectiveness of prolonged and excessive cooling on the burned wound just immediately after injury. The wound was produced by applying a lint immersed in boiled water at 99 degrees C. The wound produced by applying a lint for 3 s, and then immediately soaking with tap water for 1 min, resulted in little damage. However, the wound produced by applying a lint for 10 s, and immediately after an ice cube applied for 10 min, resulted in the most severe damage. The wound produced by applying a lint for 10 s, and no treatment applied thereafter, and the wound produced by applying a lint for 10 s and immediately after soaked with tap water for 1 min, resulted in moderate damage. From this experiment, it is suggested excessive and prolonged cooling of the burn wound, such as using an ice cube immediately after injury, is harmful in some instances.