It is very weak, for example, compared to Lightning Bolt. From the first turn, aiming Lightning Bolt at your opponent leaves you with about a 17.6% life lead over him or her; whereas a first turn Healing Salve targeting yourself leaves you with only a 15% life lead, and the opponent is no closer to death.
 Planar Chaos
Healing Salve was revisited in Planar Chaos as the green spell Healing Leaves; which is functionally identical to the original in all ways but the casting cost: instead of . Since life gain/damage prevention is less common in green than in white, Healing Leaves is not as grossly underpowered as Healing Salve, relatively speaking.