diff --git a/functions/mail.xml b/functions/mail.xml
index 17cb1a9622..f3d34b94c5 100644
--- a/functions/mail.xml
+++ b/functions/mail.xml
@@ -123,6 +123,12 @@ mail($recipient, $subject, $message, $headers);
       </programlisting>
      </example>
     </para>
+    <note>
+     <para>
+       Make sure you have no new-line (or other whitespace) after your to or
+       subject parameters, as this may cause strange results.
+     </para>
+    </note>
    </refsect1>
   </refentry>