diff --git a/src/pocketmine/PocketMine.php b/src/pocketmine/PocketMine.php
index b8f6b860c..66804a7b9 100644
--- a/src/pocketmine/PocketMine.php
+++ b/src/pocketmine/PocketMine.php
@@ -22,6 +22,9 @@
 declare(strict_types=1);
 
 namespace {
+	const INT32_MIN = -0x80000000;
+	const INT32_MAX = 0x7fffffff;
+
 	function safe_var_dump(){
 		static $cnt = 0;
 		foreach(func_get_args() as $var){
diff --git a/src/pocketmine/entity/Effect.php b/src/pocketmine/entity/Effect.php
index 9d96adf22..17ccb97f6 100644
--- a/src/pocketmine/entity/Effect.php
+++ b/src/pocketmine/entity/Effect.php
@@ -174,7 +174,10 @@ class Effect{
 	 *
 	 * @return $this
 	 */
-	public function setDuration($ticks){
+	public function setDuration(int $ticks){
+		if($ticks < 0 or $ticks > INT32_MAX){
+			throw new \InvalidArgumentException("Effect duration must be in range of 0 - " . INT32_MAX);
+		}
 		$this->duration = $ticks;
 		return $this;
 	}
@@ -248,7 +251,7 @@ class Effect{
 	 * @return $this
 	 */
 	public function setAmplifier(int $amplifier){
-		$this->amplifier = $amplifier & 0xff;
+		$this->amplifier = ($amplifier & 0xff);
 		return $this;
 	}