Poison counters are a game mechanic used in various trading card games, most notably in Magic: The Gathering. They represent a player's health status, where accumulating ten poison counters results in a loss of the game. This mechanic introduces a unique strategy, as players can win by dealing poison damage instead of reducing their opponent's life total to zero. In gameplay, certain cards or abilities can inflict poison counters on opponents. These counters are tracked separately from life points, allowing for different win conditions. This adds depth to the game, encouraging players to explore alternative strategies and tactics.