Bulk Epsom Salt, pure magnesium sulfate. Brilliant value, and excellent quality (independently tested). Meets USP38 (United States Pharmacopeia), 99.8% pure, Certificate of Analysis available to view, click here.  Epsom Salts has a long-standing reputation as a therapeutic tonic for the whole body - aiding tired, achy muscles, helpful for eczema, cramps and even asthma! Safe for children and babies. For more information on what makes Epsom Salts the best original therapeutic bath salt and its MANY other uses, a great site to have a look at is http://www.epsomsaltcouncil.org/ (external site).