DMSO is a natural solvent extracted from wood pulp.
Highest grade purity 99.9% diluted to 70% which is a safe to use concentration
Note: undiluted DMSO can be supplied for the same price as long as you are aware of the following:
1/ Undiluted DMSO solidifies in cool weather (<20 °C) and therefore needs to be warmed up before use – immerse bottle in hot water for about 1 hr.
2/ Undiluted DMSO can irritate skin.