Hoping someone here can help.
Lvl 20 Rogue. Started the Quest - Mission: Probable But Not Impossible. The one where you learn poisons.
I headed to northern Barrens. Did the double flare and salute to get the dwarf to be cool with me. Pick pocketed the goblin in front of the tower. Killed the mobs in the tower. Killed Zanzill and opened his chest.
All good. Next step has me travel to Hillsbrad to complete the quest. However, I ended up applying an Anti-Venom to myself, which dispelled Zanzill’s poison. So when I get to Hillsbrad, and the guy gives me Hinnot’s Oil - it now says, ‘nothing to dispel’ when I try to apply it.
I try going back to the tower, kill Zanzill but he doesn’t poison me. Can’t loot the chest. So I discard the whistle and the oil, hoping to reset the quest chain. But that doesn’t work. Shenthul in the Ogrimmar won’t give me the quest.
I think I’ve buggered myself. Anyone have any suggestions?
That’s odd, try to open a ticket. I always ask someone to dispel when en route to turn it in and it’s just already complete when I get there.
I just picture this rogue not having poisons for the past week and a half without thinking about opening a ticket.
Rogue might be too complex for you. Just roll Mage and spell cleave your way to 60.
try sharpening stones, they do slightly more damage than poisons (at least on low armor targets)
Quest should be doable even without the debuff. Item just won’t do anything. But you don’t need it to. There’s no point you’re already cleansed and that’s the end of the chain.
GMs don’t assist with quest bugs anymore. They tell you to abandon the quest and do it again.
Hummmm, that tends to fall in line with the expected “I know this isn’t the answer you want to hear but…” that GMs all have as the intro to their standard response template.
Unfortunately without Blizz actually having CS you’ll probably have to repeat. Are you sure it didn’t turn in? I don’t think there’s much of an indicator, you’re just now able to learn poisons at a trainer. I’d double check, then drop the quest and redo it. I know it sucks, but only a GM can do anything - and if they won’t 
In case you do have to repeat it, there are easter eggs for each floor that make your abilities 1 shot all the mobs in the tower.
Thanks for the replies.
Turns out the quest chain did complete when I cured myself. I didn’t realize it at the time, as the quest appeared bugged based on the text feedback. It ended with an error saying, there is nothing to dispel.
I didn’t realize I just had to go to a trainer to get my posion ability - I assumed it was given from the quest npc.
Upon seeing all was good, I tried to reply to my own post here to disregard this thread, but the forum wouldn’t let me post a until someone else commented. And I couldn’t delete my post without opening a ticket to Blizz. 
Anyways, I’m stabbing with toxic goo now. All good.
2 Likes
It doesn’t make it apparent. Glad you got your ability to further cripple the weaker classes of Azeroth.
Make sure you have double insta poison and keep the skill maxed and you’ll melt mobs.
1 Like
I just had the same problem, I completed the quest but a shaman dispelled the poison. I turned the quest in and went to a rogue trainer and I can’t learn poisons still . Anyone have any ideas on what to do?!
1 Like
im having the same issue right now. i cant dispell since i had someone do it on the way back, didnt know that i needed to keep the curse on me