Gavaline tea was a tea enjoyed by Betazoids.
In 2368, Deanna Troi drank Gavaline tea aboard the USS Enterprise, remembering that it was a favorite of Lwaxana Troi. (TNG novella: The Badlands, Part II)
In 2372, Lwaxana Troi asked Odo if she could use Odo's replicator to get some Gavaline tea. (DS9 episode: "The Muse")