diff --git a/src/battle_ai_switch_items.c b/src/battle_ai_switch_items.c
index b087cf3939..2fb8417ad9 100644
--- a/src/battle_ai_switch_items.c
+++ b/src/battle_ai_switch_items.c
@@ -1609,7 +1609,7 @@ static u32 GetSwitchinHitsToKO(s32 damageTaken, u32 battler)
     u16 maxHP = AI_DATA->switchinCandidate.battleMon.maxHP, item = AI_DATA->switchinCandidate.battleMon.item, heldItemEffect = ItemId_GetHoldEffect(item);
     u8 weatherDuration = gWishFutureKnock.weatherDuration, holdEffectParam = ItemId_GetHoldEffectParam(item);
     u32 opposingBattler = GetBattlerAtPosition(BATTLE_OPPOSITE(GetBattlerPosition(battler)));
-    u32 opposingAbility = gBattleMons[opposingBattler].ability;
+    u32 opposingAbility = gBattleMons[opposingBattler].ability, ability = AI_DATA->switchinCandidate.battleMon.ability;
     bool32 usedSingleUseHealingItem = FALSE;
     s32 currentHP = startingHP;
 
@@ -1631,6 +1631,10 @@ static u32 GetSwitchinHitsToKO(s32 damageTaken, u32 battler)
         // Take attack damage for the turn
         currentHP = currentHP - damageTaken;
 
+        // One shot prevention effects
+        if (damageTaken >= maxHP && currentHP == maxHP && (heldItemEffect == HOLD_EFFECT_FOCUS_SASH || (B_STURDY >= GEN_5 && ability == ABILITY_STURDY)))
+            currentHP = 1;
+
         // If mon is still alive, apply weather impact first, as it might KO the mon before it can heal with its item (order is weather -> item -> status)
         if (currentHP != 0)
             currentHP = currentHP - weatherImpact;