is being poisoned same as being leeched

let me ask better,
when im being poisoned or chaos damage and i see my life dwindling away-is that considered leeching?
so if i get that node that says "cannot be life leeched" will that completely stop the leeching poiosn or chaos damage?

No, leech refers to enemies that have the "leeches life" mod, or attack you while you have warlords mark on you.

Thanks for info
Is that a really common mod? Is it worth getting ? I'm melee