The chances of curing poison is not dependent on the type of poison the healer is trying to cure (lesser/normal/greater/deadly) but on the skill of the healer.
I have cured lesser to greater in 2 shots every time; tried each level of poison 3 times
Then I drank deadly poison and cured it in one shot
It seems as if the curing process has a chance of success equivalent to 50% of my skill
You also can get healing skill from just trying to cure poison without not having any anatomy skill at all. It's a waste of good deadly poison but if used solely for skill gain, it will work.
You are better off trying to heal someone with 3 hp left and 100 max hp. it gives .3 instead of .1
Curing success is based more on anatomy than healing but requires some of both.
At 60 healing and 60 anatomy you have a chance but it is comparable to casting eighth circle spells with 78.5 magery skill. As anatomy increases it doesn't affect chances until you get 63.5 healing; then the anatomy becomes an important factor.
