Our Hot and Cold Gel Pack help reduce swelling, toothache, temporary relief of headache and reducing fevers that causes pain. When used as a cold therapy, it provides fast first relief for acute soft tissue injuries, and other conditions that require cold applications to reduce bruising, swelling and pain. When used as a hot therapy, it provides long lasting soothing relief. It is a great source of muscle relaxation; increasing blood flow to promote healing. It can also be used to soothe arthritis pain.It can also be placed in Microwave/Freezer/Hot Water. There are plenty of other uses including keeping drinks cold in your lunch bag or keeping food hot.