A general term for compounds formed when magnesium reacts with an acid, such as magnesium sulphate, magnesium chloride, or magnesium citrate. These salts are the usual forms in which magnesium appears in foods, supplements, medicines, and mineral waters. Different magnesium salts vary in solubility, taste, and bioavailability, influencing their use: citrate and chloride are common in supplements, sulphate appears in Epsom salts and some mineral waters, and hydroxide in antacids. In food processing, magnesium salts serve as firming agents, nutrient supplements, and processing aids. Adequate magnesium intake from diet and, where needed, well-chosen salts supports the mineral’s many physiological roles.