diff --git a/wp-includes/plugin.php b/wp-includes/plugin.php
index b8bf524af..47610a360 100644
--- a/wp-includes/plugin.php
+++ b/wp-includes/plugin.php
@@ -57,7 +57,7 @@ function apply_filters($tag, $string) {
 				$string = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
 			}
 
-	} while ( next($wp_filter[$tag]) );
+	} while ( next($wp_filter[$tag]) !== false );
 
 	return $string;
 }
@@ -161,7 +161,7 @@ function do_action($tag, $arg = '') {
 			if ( !is_null($the_['function']) )
 				call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
 
-	} while ( next($wp_filter[$tag]) );
+	} while ( next($wp_filter[$tag]) !== false );
 
 }