Truffle Mushrooms

Are those elixirs really worth to craft? cause truffle mushrooms are so rare..

As the name suggests, a Truffle is an underground growing mushroom.
So in Serendia, look for the hidden caves under the naga spawns.
There you will find noumerous mushrooms + the rare Truffle.

Bring a lantern with you so you can see where your going

http://bdocodex.com/tw/gatherable/10430/

Does anyone have the success rate when using just 1 truffle mushroom?

Following Kamasylvia Part 2 expansion, truffle mushrooms can now be obtained by gathering from mushroom monsters at Polly's Forest.