Epsom Salt from AniMed is a granular powder of magnesium sulfate packaged in a resealable tub with an enclosed scoop for measuring. Formulated as a dietary supplement for horses, it supplies magnesium that plays a role in normal muscle and nervous system function, and horses lacking sufficient magnesium may show poor tolerance to work or increased sensitivity to environmental stress. The scoop measures roughly one-third of an ounce and delivers approximately 926 milligrams of magnesium per serving, with feeding amounts based on the horse's body weight. Beyond feeding, the same magnesium sulfate can be mixed into warm water for hoof soaks or made into a poultice for topical use on the lower limb. Feeding well beyond the recommended amount can produce a laxative effect, so amounts should be adjusted gradually rather than increased all at once. The powder is best kept sealed in its tub and stored in a cool, dry location between uses.