Saldruth's viper venom was a poison extracted from the fangs of the Saldruth's viper, a snake found in the Nelanther Isles. It was harvested by pirates and sold to merchants in Skullport and Waterdeep.
This viscous, white liquid tasted slightly sweet. It could be mixed with water or alcohol and ingested, or applied to a weapon and introduced into the bloodstream by injury. A single dose typically cost 300 gp.
Unless the victim was able to resist, this poison initially sapped a victims health and eventually damaged their constitution.
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 to subdue excessively rowdy customers on occasion. He was also known to sell it to people he trusted.