Poison Tolerance

A permanent with poison tolerance allows the player to temporarily accumulate more poison counters than the normal 10 that would cause them to lose the game. It is an additive effect with each permanent having the ability on the battlefield to add a varied number of poison tolerance to the player. The effect only remains while the permanents remain on the battlefield so one of them leaving the battlefield could trigger a loss of the game if the tolerance drops below the number of poison counters. It has been featured on artifacts, creatures, and enchantments on Unknown Event test cards.

The reminder text for Poison Tolerance reads "It takes an additional N poison counters for you to lose your game to poison." where N is the number printed on the card. For example, Poison Tolerance 3 means "It takes an additional 3 poison counters for you to lose your game to poison."