Source: PHB, page 145. Available in the SRD and the Basic Rules.
Black Sap
EGWp152
Adventuring gear
300 gp
This tarry substance harvested from the dark boughs of the death's head willow is a powerful intoxicant. It can be smoked as a concentrate or injected directly into the bloodstream. A creature subjected to a dose of black sap cannot be charmed or frightened for 1d6 hours.
For each dose of black sap consumed, a creature must succeed on a DC 15 Constitution saving throw or become poisoned for 2d4 hours—an effect that is cumulative with multiple doses.