One of the most common topical treatments for minor muscle and skin pain is Epsom salt, which has been used for centuries as a home remedy. You can soak bruises in water mixed with this compound. You may find some pain reduction from the use of Epsom salt, but that effect is not proven by medicine.

Epsom salt is the common name for the ionic compound magnesium sulfate. This compound is a solid, transparent crystal that collects in a white powder. Epsom salt is odorless and very safe for use, causing few problems during topical use and only low-level irritation if ingested. The salt is extremely soluble in water and should disappear quickly when added.

Users of Epsom salt claim it functions by drying the skin and helping muscle tissue relax. A small amount of the magnesium sulfate in the Epsom salt is absorbed through the skin, allowing for the release of tension. Such muscle relaxation is the reason it is used to relieve the pain of bruises. Unfortunately, there is little medical research that can either support or refute this claim.

The most important effect of Epsom salt when treating bruises is the reduction of swelling in the affected area. Research at the University of Birmingham in England in 2006 showed that Epsom salt is absorbed into the body after soaking. The Epsom salt will reach the underlying, damaged tissue of a bruise, but research is unclear as to whether this will have much effect.

To use Epsom salt to treat a bruise, add two cups of Epsom salt to a warm water bath. Soak the injured area until the water cools. After soaking, you should rinse yourself well with clean water, as the dissolved magnesium sulfate may leave dried crystals on your skin after the water evaporates. These crystals are harmless but may cause irritation.

Because Epsom salt is a commonly available treatment with a long history of use, many people think that its effects are proven. However, medical research on the properties and benefits of Epsom salt has focused primarily on internal use for the treatment of ailments like irregular heartbeat, pre-eclampsia and tetanus. Soaking in Epsom salt will cause no harm, but medicine has not proven that it works for bruises.