diff --git a/src/data/bedrock/PotionTypeIdMap.php b/src/data/bedrock/PotionTypeIdMap.php
index 2e6fef3cc..8194f24a2 100644
--- a/src/data/bedrock/PotionTypeIdMap.php
+++ b/src/data/bedrock/PotionTypeIdMap.php
@@ -84,6 +84,7 @@ final class PotionTypeIdMap{
 		$this->register(PotionTypeIds::STRONG_TURTLE_MASTER, PotionType::STRONG_TURTLE_MASTER());
 		$this->register(PotionTypeIds::SLOW_FALLING, PotionType::SLOW_FALLING());
 		$this->register(PotionTypeIds::LONG_SLOW_FALLING, PotionType::LONG_SLOW_FALLING());
+		$this->register(PotionTypeIds::STRONG_SLOWNESS, PotionType::STRONG_SLOWNESS());
 	}
 
 	private function register(int $id, PotionType $type) : void{
diff --git a/src/data/bedrock/PotionTypeIds.php b/src/data/bedrock/PotionTypeIds.php
index aa69461ce..f2d82f39f 100644
--- a/src/data/bedrock/PotionTypeIds.php
+++ b/src/data/bedrock/PotionTypeIds.php
@@ -66,4 +66,5 @@ final class PotionTypeIds{
 	public const STRONG_TURTLE_MASTER = 39;
 	public const SLOW_FALLING = 40;
 	public const LONG_SLOW_FALLING = 41;
+	public const STRONG_SLOWNESS = 42;
 }
diff --git a/src/data/runtime/RuntimeEnumDeserializerTrait.php b/src/data/runtime/RuntimeEnumDeserializerTrait.php
index c4864a7e7..4774304a9 100644
--- a/src/data/runtime/RuntimeEnumDeserializerTrait.php
+++ b/src/data/runtime/RuntimeEnumDeserializerTrait.php
@@ -190,16 +190,17 @@ trait RuntimeEnumDeserializerTrait{
 			29 => \pocketmine\item\PotionType::STRONG_LEAPING(),
 			30 => \pocketmine\item\PotionType::STRONG_POISON(),
 			31 => \pocketmine\item\PotionType::STRONG_REGENERATION(),
-			32 => \pocketmine\item\PotionType::STRONG_STRENGTH(),
-			33 => \pocketmine\item\PotionType::STRONG_SWIFTNESS(),
-			34 => \pocketmine\item\PotionType::STRONG_TURTLE_MASTER(),
-			35 => \pocketmine\item\PotionType::SWIFTNESS(),
-			36 => \pocketmine\item\PotionType::THICK(),
-			37 => \pocketmine\item\PotionType::TURTLE_MASTER(),
-			38 => \pocketmine\item\PotionType::WATER(),
-			39 => \pocketmine\item\PotionType::WATER_BREATHING(),
-			40 => \pocketmine\item\PotionType::WEAKNESS(),
-			41 => \pocketmine\item\PotionType::WITHER(),
+			32 => \pocketmine\item\PotionType::STRONG_SLOWNESS(),
+			33 => \pocketmine\item\PotionType::STRONG_STRENGTH(),
+			34 => \pocketmine\item\PotionType::STRONG_SWIFTNESS(),
+			35 => \pocketmine\item\PotionType::STRONG_TURTLE_MASTER(),
+			36 => \pocketmine\item\PotionType::SWIFTNESS(),
+			37 => \pocketmine\item\PotionType::THICK(),
+			38 => \pocketmine\item\PotionType::TURTLE_MASTER(),
+			39 => \pocketmine\item\PotionType::WATER(),
+			40 => \pocketmine\item\PotionType::WATER_BREATHING(),
+			41 => \pocketmine\item\PotionType::WEAKNESS(),
+			42 => \pocketmine\item\PotionType::WITHER(),
 			default => throw new InvalidSerializedRuntimeDataException("Invalid serialized value for PotionType")
 		};
 	}
diff --git a/src/data/runtime/RuntimeEnumSerializerTrait.php b/src/data/runtime/RuntimeEnumSerializerTrait.php
index fd65ffb42..c570046c6 100644
--- a/src/data/runtime/RuntimeEnumSerializerTrait.php
+++ b/src/data/runtime/RuntimeEnumSerializerTrait.php
@@ -190,16 +190,17 @@ trait RuntimeEnumSerializerTrait{
 			\pocketmine\item\PotionType::STRONG_LEAPING() => 29,
 			\pocketmine\item\PotionType::STRONG_POISON() => 30,
 			\pocketmine\item\PotionType::STRONG_REGENERATION() => 31,
-			\pocketmine\item\PotionType::STRONG_STRENGTH() => 32,
-			\pocketmine\item\PotionType::STRONG_SWIFTNESS() => 33,
-			\pocketmine\item\PotionType::STRONG_TURTLE_MASTER() => 34,
-			\pocketmine\item\PotionType::SWIFTNESS() => 35,
-			\pocketmine\item\PotionType::THICK() => 36,
-			\pocketmine\item\PotionType::TURTLE_MASTER() => 37,
-			\pocketmine\item\PotionType::WATER() => 38,
-			\pocketmine\item\PotionType::WATER_BREATHING() => 39,
-			\pocketmine\item\PotionType::WEAKNESS() => 40,
-			\pocketmine\item\PotionType::WITHER() => 41,
+			\pocketmine\item\PotionType::STRONG_SLOWNESS() => 32,
+			\pocketmine\item\PotionType::STRONG_STRENGTH() => 33,
+			\pocketmine\item\PotionType::STRONG_SWIFTNESS() => 34,
+			\pocketmine\item\PotionType::STRONG_TURTLE_MASTER() => 35,
+			\pocketmine\item\PotionType::SWIFTNESS() => 36,
+			\pocketmine\item\PotionType::THICK() => 37,
+			\pocketmine\item\PotionType::TURTLE_MASTER() => 38,
+			\pocketmine\item\PotionType::WATER() => 39,
+			\pocketmine\item\PotionType::WATER_BREATHING() => 40,
+			\pocketmine\item\PotionType::WEAKNESS() => 41,
+			\pocketmine\item\PotionType::WITHER() => 42,
 			default => throw new \pocketmine\utils\AssumptionFailedError("All PotionType cases should be covered")
 		});
 	}
diff --git a/src/item/PotionType.php b/src/item/PotionType.php
index 7ec0f3876..e7feb0b8e 100644
--- a/src/item/PotionType.php
+++ b/src/item/PotionType.php
@@ -65,6 +65,7 @@ use pocketmine\utils\EnumTrait;
  * @method static PotionType STRONG_LEAPING()
  * @method static PotionType STRONG_POISON()
  * @method static PotionType STRONG_REGENERATION()
+ * @method static PotionType STRONG_SLOWNESS()
  * @method static PotionType STRONG_STRENGTH()
  * @method static PotionType STRONG_SWIFTNESS()
  * @method static PotionType STRONG_TURTLE_MASTER()
@@ -201,6 +202,9 @@ final class PotionType{
 			]),
 			new self("long_slow_falling", "Long Slow Falling", fn() => [
 				//TODO
+			]),
+			new self("strong_slowness", "Strong Slowness", fn() => [
+				new EffectInstance(VanillaEffects::SLOWNESS(), 20 * 20, 3)
 			])
 		);
 	}
diff --git a/src/item/StringToItemParser.php b/src/item/StringToItemParser.php
index 46b37e3ae..e5e5252e1 100644
--- a/src/item/StringToItemParser.php
+++ b/src/item/StringToItemParser.php
@@ -1506,6 +1506,8 @@ final class StringToItemParser extends StringToTParser{
 		$result->register("strong_poison_splash_potion", fn() => Items::SPLASH_POTION()->setType(PotionType::STRONG_POISON()));
 		$result->register("strong_regeneration_potion", fn() => Items::POTION()->setType(PotionType::STRONG_REGENERATION()));
 		$result->register("strong_regeneration_splash_potion", fn() => Items::SPLASH_POTION()->setType(PotionType::STRONG_REGENERATION()));
+		$result->register("strong_slowness_potion", fn() => Items::POTION()->setType(PotionType::STRONG_SLOWNESS()));
+		$result->register("strong_slowness_splash_potion", fn() => Items::SPLASH_POTION()->setType(PotionType::STRONG_SLOWNESS()));
 		$result->register("strong_strength_potion", fn() => Items::POTION()->setType(PotionType::STRONG_STRENGTH()));
 		$result->register("strong_strength_splash_potion", fn() => Items::SPLASH_POTION()->setType(PotionType::STRONG_STRENGTH()));
 		$result->register("strong_swiftness_potion", fn() => Items::POTION()->setType(PotionType::STRONG_SWIFTNESS()));