DMSO Pure DMSO. Description: 99.9% Pure DMSO. Nature's Gift. Dimethyl sulfoxide (DMSO) is a chemical compound which is a by-product of wood processing. It is a somewhat oily liquid that looks like mineral oil and has a slightly garlicky odor. It has long been used as a chemical solvent. In the late 1960s, it also became popular as a topical pain relief medication for pulled, strained, and sprained muscles and joints. Disclaimer These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure, or prevent any disease.