what us epsum salt.. why it is used for bathing purpose

A. epsum slat has Magnesium sulfate as a medication is used to treat and prevent low blood magnesium and seizures in women with eclampsia. It is also used in the treatment of torsades de pointes, severe asthma exacerbations, constipation, and barium poisonin In water, it breaks down into magnesium and sulfate. The theory is that when you soak in an Epsom salt bath, these get into your body through your skin. That hasn't been proven, but just soaking in warm water can help relax muscles and loosen stiff joints so it is relaxing