Pippin talking about his "loveliest dream" while holding a stone dish of ent-draught
The Ent-draughts were the mysterious drafts of the Ents and possibly their primary source of nourishment in Fangorn forest.
Nothing much is known about the contents of these drinks, only that they were made from the river-water and possibly mixed with other things. They also came in two different varieties: one that refreshes and one that nourishes. They are known to have been kept in large stone jars and then ladled out into large bowls. After drinking them, the Ents preferred to lie down so that the drink would not rise immediately to their heads.
The only known recorded time that they were given to anyone outside the Ents was when Merry and Pippin took them during their time in Fangorn forest. As a result of them drinking the draughts, they grew into the largest hobbits in the Shire, adding at least two to three inches to their overall height.