Behind door number one, we have...Follow

Ok. I am a Rogue working on my alchemy skill. I have seen items like Essence of Kick and Elixer of Rejuvination. I went to Sony Station, but that does not tell ANYTHING about the item, they claim there would be info.
So can someone tell me, are these mild poisons or what are they and what are they for?
Thank you in advance.

Those are the upgrades for combat/casting skills...

Essence of Kick will upgrade Apperentice 1 to 2 or 3(depending on how well you can craft it)

Elixer of Rejuvinatino is(as you would think) a healing potion or a regeneration booster.

Almost all the potions with "Essence" in the front are Apprentice 3 or Adept 3 combat arts upgrades for fighters. (There is one called "Essence of Treefolk" that is a regular potion.) Most of the Elixirs are potions. Anything else, usually with some awful-sounding name, is probably a poison.

Some day in the future Sony will patch the game so you will know what a potion/poison does just by doing an Examine. Until then though, it's kinda guesswork as to what each does.