diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index baa334801d1..43db4f60f0b 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -548,7 +548,7 @@ function validate_param($param, $type, $allownull=NULL_NOT_ALLOWED, $debuginfo='
  * </code>
  *
  * @param mixed $param the variable we are cleaning
- * @param int $type expected format of param after cleaning.
+ * @param string $type expected format of param after cleaning.
  * @return mixed
  */
 function clean_param($param, $type) {