It is available for hot or cold compress. Necessary as a first-aid for every family! 2. For hot compress, please put in the microwavable container or cover completely iwth water at medium power setting for 30 seconds interval each time until reaching the required temperatureor sock into hot water approx. 80-90 degree Celsius for 3-5 minutes. 3. For cold compress, please place it in the freezer for an hour before using. 4. Non-toxic, Non-caustic