The cure critical wounds spell is a very potent version of the cure light wounds spell.
The priest lays his hand upon a creature and heals 3d8+3 points of damage from wounds or other damage. The spell does not affect creatures without corporeal bodies, those of extraplanar origin, or those not living.
The reversed spell, cause critical wounds, operates in the same fashion as other causes wounds spells, requiring a successful touch to inflict the 3d8+3 points of damage. Caused wounds heal via the same methods as do wounds of other sorts.