Epsom Salt is a pure mineral compound of Magnesium and Sulfate. It has multiple uses in the equine industry. Some horse owners use it as an osmotic laxative, to relieve constipation in horses. As a source of Magnesium and because it is easily absorbed by the skin, Epsom Salt can be used to reduce inflammation, by applying under bandages on the horse's legs. Magnesium also aids nerve and muscle function, hence its calming effect.