How do you use the green potion, forget it's name but it's the one which poisons you. I've tried clicking it on to my weapon, tried right clicking on it while in my belt at the bottom of the screen but I just get poisoned. I have an awful feeling I'm missing something obvious... Thanks.
It's only use is as a reagent in a poison trap and wand and maybe a poison encrust, I don't remember. I'm assuming you're asking if you can directly apply it to a weapon to get a temporary vile poison buff, which unfortunately you can't to my knowledge. I believe you get that in burglary though. Edit: Or if you're really crazy you might be able to transfer the poison debuff from drinking it to an enemy with magic law.