Talk:Toxic (Dark Souls)/@comment-24543527-20140221192939/@comment-6003396-20140222064045

Under "Defense" it reads: Even though the value is normally not displayed, increasing Toxic Resist can be accomplished by increasing Poison Resist, with the exception of the Poisonbite Ring, which only defends against Poison.

So they are separate stats, but nearly everything that raises Poison Resistance will raise Toxic Resistance as well.