diff --git a/app/controllers/documents_controller.php b/app/controllers/documents_controller.php
index f79106bb..e9cf6cf4 100755
--- a/app/controllers/documents_controller.php
+++ b/app/controllers/documents_controller.php
@@ -928,7 +928,7 @@ EOT;
           return;
         }
         
-        $this->Email->subject = $this->po_email_subject($document['PurchaseOrder']);
+        $subject = $this->po_email_subject($document['PurchaseOrder']);
         $this->Email->to = $this->email_format($primary_contact['User']['email']);
         $this->Email->replyTo = null;
         $this->Email->cc = null;