[curiouscat]

I always regarded  Dimethyl Sulfoxide as a nasty, toxic reagent but just now I came across a Lab Safety summary (link below) that says:

Acute toxicity by all routes is very low. Material is only slightly toxic by ingestion. Relatively non-toxic by skin absorption. Not found to be carcinogenic. No developmental or reproductive effects.

http://www.nap.edu/openbook.php?record_id=4911&page=302

Is this really true? Is DMSO more seemingly nasty (smell, irritant etc.) than actually nasty?

[discodermolide]

It's not toxic. The smell comes from small amounts of dimethylsulfide.
Some people may show skin irritation but it is used as a diluent for some drugs to get them through the skin.

[curiouscat]

It's not toxic. The smell comes from small amounts of dimethylsulfide.
Some people may show skin irritation but it is used as a diluent for some drugs to get them through the skin.

Thanks @disco.

A follow up question: I've a quantity of DMSO we no longer need. The ultimate option is to pay a hazmat firm to take it away but are there any easier ways to render the stuff more innocuous? Perhaps less smelly at least.

What are typical options for DMSO spills?

[discodermolide]

Just wash it away with water, it is biodegradable. A trace of bleach will remove the smell if present.

[curiouscat]

Just wash it away with water, it is biodegradable. A trace of bleach will remove the smell if present.

Thanks!

[Dan]

It's not toxic. The smell comes from small amounts of dimethylsulfide.
Some people may show skin irritation but it is used as a diluent for some drugs to get them through the skin.

To add to this, it's not the DMSO that is dangerous, it is the fact that it acts as a skin contact delivery system for whatever you have dissolved in it - i.e. the risk posed by a toxic compound through skin contact is usually much higher if it is dissolved in DMSO.

[curiouscat]

To add to this, it's not the DMSO that is dangerous, it is the fact that it acts as a skin contact delivery system for whatever you have dissolved in it - i.e. the risk posed by a toxic compound through skin contact is usually much higher if it is dissolved in DMSO.

Yup. True.

Not an issue in my case since this is neat DMSO. Unused.

[DMSO]

Yes DMSO is not the toxic component its what may be dissolved in DMSO which is the concern.