Subject: What is produced which causes stinging from stinging nettles?

I have read many different accounts telling me different things as to what is 
produced by stinging nettles when they sting, i.e. What substance causes the 
stinging pain. I read that formic acid is produced. I read somewhere else that 
it is acetyl choline which is produced. I still am uncertain as to what is the 
cause of the sting and how it causes it. I also am unsure as to which treatment 
works best and why. Would it be anti histamine creams, steroid cream or just the 
rubbing of the common dock leaf?

Re: What is produced which causes stinging from stinging nettles?