Does Negative Poison Heal Mobs?

I'm pretty sure lifesteal/manasteal work like that, but not certain about poison.

 

No it doesn't for both of those. Negative lifesteal and mana steal make you lose mana/hp if it procs when you melee, and does not affect the mob. All -poison does however is to make you lose any higher poison damage you could do. Ex. a weapon has -4k poison, which makes it very difficult to get positive poison. The only thing that -poison might do is break mobs out of wind prison from when they're trapped in wind prison, but don't take my word on that because otherwise it does nothing