diff --git a/wp-admin/includes/plugin.php b/wp-admin/includes/plugin.php
index be5f28cd01..5d2570ca52 100644
--- a/wp-admin/includes/plugin.php
+++ b/wp-admin/includes/plugin.php
@@ -291,7 +291,7 @@ function get_plugin_page_hook( $plugin_page, $parent_page ) {
 	if ( isset( $wp_filter[$hook] ))
 		return $hook;
 	else
-		return '';
+		return null;
 }
 
 function get_plugin_page_hookname( $plugin_page, $parent_page ) {
@@ -377,4 +377,4 @@ function user_can_access_admin_page() {
 	return true;
 }
 
-?>
\ No newline at end of file
+?>