Cold packs and hot packs are therapeutic bath and beauty supplies, which help encourage relaxation, promote tranquility, and help relieve pain, inflammation, and discomfort. Cold packs, also known as ice packs, contain a gel or liquid that stays cold when frozen, while some hot packs can be heated using a microwave or filled with hot water to provide warmth. In some cases, like a heated eye mask, a battery or electrical outlet is used to gently heat the pack. For the best of both worlds, look for hot and cold packs, which often use a gel that can either be heated or cooled depending on your needs.