For people who are wondering about the Inf Health, what the Inf cheats basically do, is lock your health and mana to be always at least 7-8 while hunger does tend to not decrease at all... i -think-.
Add Exp... I have no idea what it's intended function is, if that could be clarified.
(This does mean that Mana can regenerate above the locked value and health can be recovered to its actual max value without conflicting as well. Even if the game does show your health at 3 or 5, etc depending on how much you got hit with, the actual value of your health will never drop below that 7-8, even if the health bar doesn't show it at all times.)
But basically, the way the Inf Health works, is that as long as you don't get hit by an attack or spell that deals at least 8 damage, you can't die. Enemies can wail in packs down on you, but as long as not a single hit deals at least 8 damage, your char will outright not die.
(Ofcourse, if your health is below 8, lesser damaging hits CAN kill you if the damage dealt is AT LEAST the same value as your max health.)
Few examples of confirmed enemies that can kill you despite the Inf Health: Red Dragon in the Volcano biome, Black Dragon miniboss in the Volcano biome, Minotaurus enemies in the Dungeon biome and the spear wielding enemies in the Scourge biome.
Haven't tested all mobs, but I imagine that the Skeleton King might very likely be able to kill you too, seeing the Volcano and Dungeon being around the same 'difficulty'. The projectiles from the Wall of Scourge and the floating Scourge ghosts don't seem to deal enough damage to kill you outright, luckily enough.
Hope that helps.