Nightviper venom

Nightviper venom was a poison extracted from the fangs of the nightviper, a snake found in the Nelanther Isles. It was harvested by pirates and sold to merchants in Skullport and Waterdeep.

Description
This milky white liquid had a slightly sweet taste. It could be mixed with water or alcohol and still retain its potency. It could also be administered through an open wound caused by a weapon treated with this substance. A single dose typically cost 600 gp.

Effects
Unless the victim was hardy enough to resist, this poison impaired a victim's judgement. Effects ranged from merely reducing inhibitions and making bad choices to falling into a complete stupor.

Notable Users
Elsk Thavarask, the proprietor of the Missing Minotaur tavern in Everlund, circa the Year of Wild Magic, 1372 DR, was known to use this substance on occasion, and perhaps sell it to people he trusted.