The Taurogrim bear a potent, but curable poison. Without a steady supply of Celeblam, their corruption will spread too quickly to contain.
'With the Taurogrim encroaching on Eryn Lasgalen, it is unavoidable that more innocents will fall victim to their poisons. We shall have need of more of Thorlind's curative draught, and I would ask for your aid in this task.
'Gather more Celeblam in the forest and deliver it to me as swiftly as you are able!'
Celeblam flowers can be found in Eryn Lasgalen.
Thranduil has asked you to gather Celeblam for the Elves of Eryn Lasgalen so that Thorlind can craft more of his healing draught.