Antidotes often grow from the same soil as poisons; herbs from near the sickly pool should be collected so that the Elves can examine them for medicinal properties.
'There is a phenomenon that often happens in nature in which remedies grow hand-in-hand with poisons. Weeds that harm can often be found nestled amongst leaves that cure. Now that we know just where the source of this strange illness lies, we should search the area for any plants which may have grown to resist the harmful environment.
'If you see any plants that seem to stand out, can you collect them for me? I believe we can devise a remedy if healing herbs can be unearthed from this polluted swamp.
'Return to that sickly place, ${PLAYER}, and make haste. Collect as many plants as you can. Please hurry! Alagos is fading....'
Plants can be found growing near the dreadful pool in the Drownholt, south from Estolad Mernael.
You should hasten to the pool and collect many herbs there, for these may possess some property that could heal the steed Alagos.
Nestawen can be found at Estolad Mernael, tending her sick steed Alagos.
You should bring the plants and flowers you collected to Nestawen to see if they can be of any use to her.