The fact that DMSO arrives frozen and thus solid, especially in colder months, is completely normal and no cause for concern. So please don't be surprised if you buy DMSO from us: The fact that the substance freezes is due to its characteristic melting point of +18 °C. Below this temperature, dimethyl sulfoxide crystallizes. For comparison: Water freezes at 0 degrees, so it is still liquid in a cold environment just above that, DMSO, on the other hand, becomes solid before that. In this case, simply place the bottle next to a heater, after a certain time you can already observe how the DMSO slowly becomes liquid again. If DMSO is mixed with water (it can be mixed in any ratio), the freezing point drops.