diff --git a/system/core/Input.php b/system/core/Input.php
index 544b7c0..ada9fc6 100644
--- a/system/core/Input.php
+++ b/system/core/Input.php
@@ -766,7 +766,7 @@
 	 *
 	 * @param	string		$index		Header name
 	 * @param	bool		$xss_clean	Whether to apply XSS filtering
-	 * @return	string|bool	The requested header on success or FALSE on failure
+	 * @return	string|null	The requested header on success or NULL on failure
 	 */
 	public function get_request_header($index, $xss_clean = FALSE)
 	{