The "cure-all" that Alice offers Catherine is from Coryana, and made from a "desert rose". In Batwoman (Rebirth), the Desert Rose was a bar located on the island of Coryana.
Catherine mentions Riddler at the gala event, a reference to Edward Nygma aka The Riddler. He was previously referenced in the episode "Down, Down, Down".
The title is a reference to 'Alice's Adventure in Wonderland', Chapter Vll: 'A Mad Tea-Party'.
The episode's title was also the title of an episode of The Adventures of Batman (1968) (Simon the Pieman/A Mad Mad Tea Party (1968)).