Despite the fact that this is a weak item, it can sometimes be a nuisance. You don’t want to focus on a tank during teamfights, and you especially don’t want to reduce healing received. Some of the ways of countering Thornmail include increasing your lifesteal and regeneration, increasing armor penetration so you can quickly nuke the user, or simply increasing your health pool so that you’re not endangered by Thorns damage or grievous wounds.