I first started seeing the "dihydrogen monoxide" or "DHMO" memes a couple of decades ago when there were serious concerns about DMSO (dimethyl sulfoxide), a sol

I first started seeing the "dihydrogen monoxide" or "DHMO" memes a couple of decades ago when there were serious concerns about DMSO (dimethyl sulfoxide), a solvent that can carry drugs through the skin, which apparently has some medical use but can be risky. It's a by-product of paper making.