Epsom salts

Epsom salts is a common name for hydrated magnesium sulfate, MgSO₄, used as a therapeutic bath, taken orally as a laxative, and to treat heartburn or constipation, and injected to prevent seizures.

Originally prepared by boiling down mineral waters at Epsom, England and afterwards prepared from sea water. In more recent times, these salts are obtained from certain minerals such as siliceous hydrate of magnesia[?].