diff --git a/src/pf1e_simulator/combat.py b/src/pf1e_simulator/combat.py
index 8af6ccd..f6dc0f2 100644
--- a/src/pf1e_simulator/combat.py
+++ b/src/pf1e_simulator/combat.py
@@ -8311,15 +8311,21 @@ def _find_heal_spell(engine: CombatEngine, spells_known: list[str]) -> str | Non
 
 
 def _find_ally_needing_heal(engine: CombatEngine, caster: CombatantState) -> CombatantState | None:
-    """Find an ally below half HP.
+    """Find a living ally below half HP.
 
     ``hp * 2 < hp_max`` is strictly-below-half for every hp_max; the old
     ``hp < hp_max // 2`` floored the threshold (hp_max 5 -> 2), so a level-1
     character at 2/5 hp counted as healthy.
+
+    Living-only (SRD Channel Energy: heal mode heals living creatures; undead
+    take damage from positive energy, never healing): an undead ally below
+    half must not trigger the heal paths - channel heal would spend the
+    channel without helping it, and a cure spell would hurt it.
     """
     for ally_state in engine.states:
         below_half = ally_state.hp * 2 < ally_state.combatant.hp_max
-        if ally_state.side == caster.side and ally_state.active and below_half:
+        living = ally_state.combatant.creature_type == "living"
+        if ally_state.side == caster.side and ally_state.active and living and below_half:
             return ally_state
     return None
 
diff --git a/tests/test_class_abilities.py b/tests/test_class_abilities.py
index bec977f..b5deea8 100644
--- a/tests/test_class_abilities.py
+++ b/tests/test_class_abilities.py
@@ -156,6 +156,24 @@ def test_oni_silent_when_channel_energy_exhausted() -> None:
     assert not any(a.kind == "channel_energy" for a in actions)
 
 
+def test_oni_no_channel_heal_trigger_for_undead_ally() -> None:
+    """SRD Channel Energy: heal mode heals living creatures. An undead ally
+    below half cannot benefit (positive energy harms undead), so it must not
+    trigger the heal mode - the channel would be spent healing nobody."""
+    oni = _combatant("oni", resources={"channel_energy": 6}, hp_max=30)
+    goblin = _combatant("goblin", hp_max=6)
+    engine, me, _ = _engine(oni, [goblin])
+    undead_ally = _state(
+        _combatant("ghoul", hp_max=20, creature_type="undead"),
+        "players", (5, 5), hp=5,
+    )
+    engine.states.append(undead_ally)
+
+    actions = default_policy(engine, me)
+
+    assert not any(a.kind == "channel_energy" for a in actions)
+
+
 def test_oni_channel_energy_spends_resource() -> None:
     oni = _combatant("oni", resources={"channel_energy": 6}, hp_max=30)
     goblin = _combatant("goblin", hp_max=6)