diff --git a/includes/common.inc b/includes/common.inc
index 075a840..288b3c6 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -964,7 +964,7 @@ function t($string, $args = array(), $langcode = NULL) {
  */
 function valid_email_address($mail) {
   $user = '[a-zA-Z0-9_\-\.\+\^!#\$%&*+\/\=\?\`\|\{\}~\']+';
-  $domain = '(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.?)+';
+  $domain = '(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])(\.[a-zA-Z0-9]+)+)+';
   $ipv4 = '[0-9]{1,3}(\.[0-9]{1,3}){3}';
   $ipv6 = '[0-9a-fA-F]{1,4}(\:[0-9a-fA-F]{1,4}){7}';