Needing clarification!

I am a firm believer in DMSO for it's penetrating capability, but could use 
some clarification.

I've always bought mine where I buy livestock supplies because I'm generally 
using it on livestock.  I know it is sold in a multitude of other places, but 
it is generally cheaper at the feed store.

In the discussion list when it came up about adding it to the CS as a 
mouthwash, I had questions come to mind about quality of DMSO.

Because I am using it to add to my IV CS infusion, I think the question of 
purity needs to be addressed.  

Looking at the label on the container we use at my house for animals and 
humans, it reads "For chemical use only - not for drug use".  I assume they say 
that as a disclaimer because the FDA certainly doesn't want people using 
something that actually helps with so many things.

Looking at the vial for IV use, I see no "disclaimer" and don't see any mention 
of the word "sterile".  Since I don't exactly understand how the DMSO is 
extracted in the first place, I probably should look into that before I show my 
ignorance too far; however, in the name of expediency, let me just announce my 
ignorance and move on!

The doctor who established my IV CS protocol said himself that what he is 
providing me is probably the same as what I buy at the feed store except this 
for IV is sterile.

I know from experience that DMSO is being sold by the gallon in many places and 
I feel like much of it is as pure  can be.  I do know that a gallon I bought at 
a flea market was not pure.  Those of us who have used it very much know pretty 
quick when we got "a watered down version thereof"!  My bargain was a bummer!

I have also noticed that this vial for IV use does not say that it is regulated 
by prescription.  Not surprising either since the FDA says it's not for 
medicinal use in the first place!

I know I don't want to be putting questionable DMSO in my veins and preferably 
like to feel like what we use for the family and animals is a good quality.    
I have seen a few cases where pet owners soaked an animals open wound with DMSO 
without regard to the caustic effect.  One animal died.  In testing, the blood 
had absorbed toxic amounts of DMSO.  In another case, the wound was exacerbated 
from irritation from too much DMSO.

So, could somebody help me out here.  I'm running my CS infusion right now with 
the DMSO in it and feel very secure in doing so because I have faith in my 
doctor.   Likewise, have used it as an adjutant in a similar mix for horses, 
but feel like care is called for in establishing a protocol with great 
consideration given to quality and quantity.

Thanks,
Barbara