Bath salts can be beneficial for many skin types. Salts and minerals, regardless of their source, can soften water and, depending on the specific salts used, reduce inflammation and swelling. Epsom salts are probably the best-known type; they work quite well and are wonderfully inexpensive. Most of the salts added to bath products are just fine, although ingredients such as borax, sodium sesquicarbonate, sodium carbonate, and phosphate can cause irritation and probably should be avoided. Table salt and sea salt can also be a problem, because if they don’t get rinsed off well they can pull water from the skin and cause dryness and irritation.
Many cosmetics lines, particularly spa lines, brag about how their products contain minerals from all kinds of sources: mineral springs in France, volcanic waters in Italy, Dead Sea salts from Israel, and on and on. The question is whether minerals and salts from exotic sources have any special effect on skin. In the long run, unless you have a skin disorder such as psoriasis or seborrhea, those salts and minerals have no positive effect. Epsom salts are preferred both for their skin-softening and anti-inflammatory properties, and because they pose a minimal risk to sensitive skin.