This is a bug i found about (the hard way) on my server. it's a 3.0.9 server.
Wound Poison - WoWWiki - Your guide to the World of Warcraft
Nice poison. great against casters. even better when different ranks of it stack reducing healing by 100%. that's right0 healing.
just get rank VI and VII , apply one to main hand and the other to offhand and voilano more healbots
i hope this works on other servers it's only tested & working on mine.