Common ProblemsI've completed the quests for the poison ability, however I still don't see the skill or have an ability for it.
There are two quests that are needed to obtain Poisons for your Rogue, and both have the same name. The quest that rewards the skill to craft potions is Hinotts Assistance.
Wrath of the Lich King Classic
Poisons do not require a skill, but are sold from vendors in most quest hubs, ready-made, by Reagent, Supply & Poison vendors. Poisons still require a minimum level to use.