diff --git a/src/pocketmine/command/defaults/EffectCommand.php b/src/pocketmine/command/defaults/EffectCommand.php
index 60fb6972d..732b5713b 100644
--- a/src/pocketmine/command/defaults/EffectCommand.php
+++ b/src/pocketmine/command/defaults/EffectCommand.php
@@ -80,7 +80,10 @@ class EffectCommand extends VanillaCommand{
 		$amplification = 0;
 
 		if(count($args) >= 3){
-			$duration = ((int) $args[2]) * 20; //ticks
+			if(($d = $this->getBoundedInt($sender, $args[2], 0, INT32_MAX)) === null){
+				return false;
+			}
+			$duration = $d * 20; //ticks
 		}else{
 			$duration = null;
 		}