As I recall it, it was merthiolate that stung. Mercurochrome was very mild.
I dunno where you got your mercurochrome, but 'round here, the mercurochrome stung like a mo@#$*%(#%er.
This & merthiolate both gave me a mild allergic reaction. Thus, when asked “Are you allergic to any drugs” I have always mentioned these. Used to be it was “Good to know”. Now it’s "Huh? 
".
Should I stop mentioning my reaction to these now- extinct medicines?
Perhaps you are thinking of Iodine - ouch !!! Now that hurt.
Mercurochrome does not sting.
I remember my grandmother using that stuff on us–it really did sting! Whether it was mercurochrome or merthiolate, I don’t know for certain–we always called it “monkey blood” anyway. I haven’t the faintest idea why! 
Mercurochrome left a reddish stain. Merthiolate left a yellowish stain. We had both in our house. Whatever brother started the altercation got merthiolate. The rest got mercurochrome.
I’m with you Mayflower - we used to call it Monkey Blood, which added a sense of mystery to your wound …wondering how much monkey blood would be absorbed and if we’d start exibiting monkey like behavior 
Holy Crap!!
I still have a bottle of the stuff in my medicine chest. (I’m still in my childhood home, while the folks moved away.) This stuff dates back to at least 1985. And, sure enough, as Liberal stated, it’s Osco’s Tincture Merthiolate that I was remembering. I’m sure we must have also had mercurochrome at some point, but the stuff I was thinking of is the merthiolate. (Although now it seems that mercurochrom does sting if it’s alcohol-based.)
In the 1970’s,we had an awesome wound-cleansing liquid called “Zepherine”. It was painless unlike soapy water, iodine, etc. By the mid-1980’s, IIRC, it was gone! Where did it go and why? Is it for the same reasons as Mercurochrome?
- Jinx
I’m not yet 30, but I’m familiar with mercurochrome. We had it in the first aid kit on a canoeing trip in Boy Scouts. Boys being boys, there were several opportunities to use it, too. I don’t remember it stinging at all, but I do remember that it changed color dramatically on contact with water (as I recall, from a yellowish-orange to a bright Rudolf-the-reindeer red).