diff --git a/system/libraries/Validation.php b/system/libraries/Validation.php
index c28713c..79ab76c 100644
--- a/system/libraries/Validation.php
+++ b/system/libraries/Validation.php
@@ -518,7 +518,7 @@
 	 */	

 	function alpha_numeric($str)

 	{

-		return ( ! preg_match("/^([-a-z0-9])+$/i", $str)) ? FALSE : TRUE;

+		return ( ! preg_match("/^([a-z0-9])+$/i", $str)) ? FALSE : TRUE;

 	}

 	

 	// --------------------------------------------------------------------