MtG: Can poison counters be removed?

Question

Is there some way to remove or counteract poison counters? Specifically, once you've already accumulated them, not when you are dealt them.

For example, say I already have 9 poison counters. Is there some way to reduce this number?

Answer 1

Counters can be removed.

However, I believe there is only one card that currently removes poison counters, and that is Leeches

Target player loses all poison counters. Leeches deals 1 damage to that player for each poison counter removed in this way.

Leeches was in the Homelands set.

Answer 2

Another way to reduce the number of poison counters that you have is through an effect that restarts the game, like Karn Liberated's third ability. Doing so resets your number of poison counters to zero, as per the New Phyrexia FAQ.

Answer 3

Check out this column, by Magic head honcho Mark Rosewater: Something Wicked This Way Comes.

It explains some of the thinking behind "modern" poison, most relevantly why you'll have trouble finding any other card that can reduce your poison total apart from Leeches. Here's a taste:

My hatred of Leeches did one important thing. It cemented in me the importance of poison not just being another life total. (This theme will become very important in Scars of Mirrodin's design.) As such, you will not see any card in the entire Scars of Mirrodin block that removes poison. It cannot be done. There are answers. There are ways to deal with poison but healing yourself of it is not one of them. If you want to remove poison counters you will only have one way—Leeches.