diff --git a/include/constants/battle_config.h b/include/constants/battle_config.h
index 80bf559209..0406d20a98 100644
--- a/include/constants/battle_config.h
+++ b/include/constants/battle_config.h
@@ -108,6 +108,7 @@
 #define B_PSYWAVE_DMG               GEN_7 // Psywave's damage formula. See Cmd_psywavedamageeffect.
 #define B_PAYBACK_SWITCH_BOOST      GEN_7 // In Gen5+, if the opponent switches out, Payback's damage will no longer be doubled.
 #define B_HIDDEN_POWER_DMG          GEN_7 // In Gen6+, Hidden Power's base power was set to always be 60. Before, it was determined by the mon's IVs.
+#define B_ROUGH_SKIN_DMG            GEN_7 // In Gen4+, Rough Skin contact damage is 1/8th of max HP instead of 1/16th. This will also affect Iron Barbs.
 
 // Type settings
 #define B_GHOSTS_ESCAPE             GEN_7 // In Gen6+, Ghost-type Pokémon can escape even when blocked by abilities such as Shadow Tag.
diff --git a/src/battle_util.c b/src/battle_util.c
index 33dd0f5de1..9515a1f325 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -4884,7 +4884,11 @@ u8 AbilityBattleEffects(u8 caseID, u8 battler, u16 ability, u8 special, u16 move
              && TARGET_TURN_DAMAGED
              && IsMoveMakingContact(move, gBattlerAttacker))
             {
-                gBattleMoveDamage = gBattleMons[gBattlerAttacker].maxHP / 8;
+                #if B_ROUGH_SKIN_DMG >= GEN_4
+                    gBattleMoveDamage = gBattleMons[gBattlerAttacker].maxHP / 8;
+                #else
+                    gBattleMoveDamage = gBattleMons[gBattlerAttacker].maxHP / 16;
+                #endif
                 if (gBattleMoveDamage == 0)
                     gBattleMoveDamage = 1;
                 PREPARE_ABILITY_BUFFER(gBattleTextBuff1, gLastUsedAbility);