Instructions
Travel with the affected character to the nearest Temple of Amn. For a donation of 750 gold pieces, the priests at the temple will cast the spell Greater Restoration on the character. Restoration cures all poisons and diseases and reverses the effects of a Level Drain.
Use a Restoration spell scroll on the affected character. The effects of the scroll are identical to those of the Greater Restoration spell. Restoration scrolls may sometimes be purchased from temples. They may also be purchased from scroll sellers found in Baldur's Gate at the Promenade, in the Slums and near the Docks. The base cost is 1,000 gold pieces, although the exact cost may vary according to your character's reputation.
Cast the spell Lesser Restoration on the affected character, if your party includes a Cleric class character able to use the spell. Lesser Restoration is a Fourth Circle spell, so your cleric needs to be at least a seventh-level character in order to use it.