Whats even worse, only one type of poison works.

(There are 4 different 1d4 poisons in this game as far as i know ... //edit: Yup:
1,
2,
3,
4.)
There is also second keg of beer you can poison later in game.

I asked for other mixures sometime around Patch 2-3 ... seems like Larian didnt find my idea to be good enough.

But i still think it would be cool:
Beer + Sleep potion > Put whole goblin camp to sleep.
Beer + Healing Potion / Antitoxin > Whole goblin camp will become sober, and pissed.
Beer + Any resistance potion > Whole goblin camp would be resistant to that damage during Grove attack. (in my opinion clasic evil move, if you plan to turn against the Grove)
Beer +
Insanity's Kiss (potion from Auntie Ethel) > All goblins will become IMEDIATELY hostile to each other. >:]