For sprains and strains, the recommended first aid is rest, ice, compression and elevation — often remembered by the acronym "RICE." Instant cold packs are a great stand-in for a conventional ice bag. They're portable, convenient and clean. They come in two basic types: a chemically-activated pouch that requires no refrigeration and a flexible gel that does. To choose the best instant cold pack, consider where it is most likely to be used, the type of injury it is most likely to treat and the person who is most likely to require treatment.

A chemically activated instant cold pack fits easily into a gym bag or first aid kit, which makes it much more portable than a gel pack that must be kept in a freezer. For quick treatment of injuries that occur where no freezers are nearby, such as many places where outdoor activities are held, a chemically activated instant cold pack is the best choice. Inside this type of cold pack's tough plastic outer envelope are two pouches of ammonium nitrate or ammonium chloride and water. You squeeze the pack to break the inner pouches and shake the pack to mix them together. This produces a chemical reaction that causes the pack to become cold.

An instant cold pack lasts for 15-30 minutes, depending on the brand, and can be used only once. For injuries that will require repeated applications of ice, a gel pack is more suitable than a chemically activated pack. Although first aid experts advise putting a barrier between the skin and an ice pack to prevent frostbite, most instant packs do not get cold enough to require this. Users should read the directions on the package to make sure.

Discount stores usually stock instant cold packs in the first aid section near the splints and braces. They cost very little and can be bought in bulk online. They are a good choice for companies, schools and individuals looking for a fast, non-messy way to provide cold therapy.

Gel cold packs are reusable but need to be refrigerated or frozen before use. They might not be practical if you have no way to cool them, and they cost a bit more than the instant variety. A gel pack is usually bigger than a chemically activated instant cold pack and fits over a larger area of the body. Some of them can also be microwaved for heat therapy, doubling their usefulness.

Some companies sell cold packs with cartoon characters or animals printed on them. These are designed to appeal to children. A familiar and beloved character might help comfort a distressed child a parent treats the injury. This type of instant cold pack can be a great choice to keep on hand if you are a parent or a youth sports coach.

Make sure to avoid puncturing the outer envelope of instant cold packs, because ammonium nitrate can burn the skin. Gel packs are usually safe, but you should avoid ingesting the ingredients of either type. They should be kept out of the reach of children.

A homemade recipe for a reusable instant cold pack calls for mixing one part isopropyl alcohol, also called rubbing alcohol, with two parts water. It can then be frozen in a zip-top plastic bag. The alcohol will prevent the water from freezing completely, allowing the the pack to remain flexible. In a pinch, a bag of frozen vegetables such as peas or corn works if nothing else is available.