Inflict Light Wounds

(Player's Handbook v.3.5, page 244, DnD 3.5)

Necromancy

Level: ; Cleric 1; Dread Necromancer 1; Blighter 1; Death Master 1; , Destruction 1
Components: V, S
Casting Time: 1 standard action
Range: Touch
Target: Creature touched
Duration: Instantaneous
Saving Throw: Will half
Spell Resistance: Yes

When laying your hand upon a creature, you channel negative energy that deals 1d8 points of damage +1 point per caster level (maximum +5).
Since undead are powered by negative energy, this spell cures such a creature of a like amount of damage, rather than harming it.