Red leaf tea was a Cardassian hot beverage, a tea with a garnet-red color and a rather sweet and spicy taste.
Red leaf tea was Elim Garak's favorite breakfast beverage, and Julian Bashir enjoyed it with his scones and Moba jam. (DS9: "The Wire", "Inquisition")
After dismissing Chief O'Brien's assistance, Gilora Rejal asked that he retrieve some red leaf tea for her. Acknowledging the not-so-subtle dismissal, the Chief complied. (DS9: "Destiny")
In the middle of a crisis on Deep Space 9, Dukat ordered red leaf tea as he was mocking the crew stationed in Ops. (DS9: "Civil Defense")