User blog comment:Zombotanist/PvZ Heroes Plant Class idea/@comment-4024597-20160729033301/@comment-25982947-20160729034322

You can't stack poison, it's a condition that zombies have, like frozen. As for the duration I'm indecisive, my initial thought is that it never goes away, so it's basically like destroying a zombie, but with the actual death being delayed, but with it doing 2 damage that might get really OP really quickly. So I guess the best thing would be reducing the poison damage to 1 per turn and leave poisoned zombies poisoned forever, (unless they were to add cards for zombies to cure poison).