Doctor Sintar Malefious at Agmar's Hammer in the Dragonblight wants you to collect 1 Ruby Lilac.
How fortuitous it is that the Ruby Dragonshrine lays just to the east. It is there that you will find a flower called the ruby lilac. This lifegiving plant is all that I need to concoct a vaccine for the untainted beasts of this region.
Travel east and search the Ruby Dragonshrine for the lilac.
Just one thing: The dragonshrine, like all the dragonshrines in this blasted wasteland, is beset by the Scourge. Watch your step. We wouldn't want you to be devoured by an emberwyrm.