DMSO (dimethyl sulphoxide) is an organic solvent with a slightly oily consistency that can be extracted from tree wood. MSM, which contains sulphur, is a close relative of DMSO, but the two substances are only chemically similar.
DMSO is hygroscopic (water-binding) and is very easy to mix with water.
The melting point of DMSO is 18°C, and under this temperature DMSO will crystallise. This process in reversible, and from temperature of 20-22°C the DMSO becomes fluid again. To liquify the DMSO, place the glass bottle in warm (not hot) water. Do not place in the microwave, as this destroys the structure of the DMSO.