Elven Holy Water

Elven Holy Water can be used to fight at least vampires and it may be used against other undead creatures as well. It can be used to prevent the pools of blood restoring health to the vampires in Bodhi's Lair. This item appears in Baldur's Gate II: Shadows of Amn and this item will probably appear in Baldur’s Gate II: Enhanced Edition. In Shadows of Amn, you gain three units from Elhan when you have agreed to hunt down Bodhi.

In Throne of Bhaal, this is sold in the temple of Saradush. One unit is required to bless the remains of spirit which may not go the afterlife.

In-game description
"Holy water blessed by the Elven god Rillifane. The water is specially made to combat vampires."