Abridged History of the 10th Age
Sleeping poison (karbash in the Essadi dialect) is a semi-magical substance that was invented by the Essadi to help capture and subdue slaves. It’s concoction is a secret shared only by the alchemical guilds of Essad; thus, acquiring it outside of that land is an expensive proposition.
Whatever the process, the end result is a thick ointment that smells vaguely of alcohol. This ointment, when smeared on a cloth and held over the target’s mouth, will affect the central nervous system, sending the target into a deep and dreamless sleep. It is dangerous, however, as there are those who have been known not to wake.
Furthermore, some thieves have experimented with this ointment on their blades. The result is not sleep, but rather the wounds made by these blades tend to become horribly swollen and pain the wounded unmercifully for several weeks.