Desegranine was a Cardassian drug used to reverse memory loss.
The drug was used by the Obsidian Order during the 24th century to help its undercover agents remember their true identities. When used, memories began to resurface within a few hours.
Corbin Entek administered a dosage of desegranine to Kira Nerys in 2371, in a failed attempt to revive the non-existent memories of Iliana Ghemor. (DS9: "Second Skin")