Lexorin was a drug.

Suffering from the residual effects of a mind meld and his cerebral cortex acting as Spock's katric ark, Dr. Leonard McCoy received a dose from James T. Kirk. The admiral needed the doctor stabilized for a "long voyage ahead" of them. (TOS movie: Star Trek III: The Search for Spock)

ConnectionsEdit

• Lexorin article at Memory Alpha, the wiki for canon Star Trek.