diff --git a/reference/url/functions/urldecode.xml b/reference/url/functions/urldecode.xml
index dba09edd34..eab008d126 100644
--- a/reference/url/functions/urldecode.xml
+++ b/reference/url/functions/urldecode.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.7 $ -->
+<!-- $Revision: 1.8 $ -->
 <refentry xml:id="function.urldecode" xmlns="http://docbook.org/ns/docbook">
  <refnamediv>
   <refname>urldecode</refname>
@@ -64,6 +64,17 @@ while ($i < count($a)) {
   </para>
  </refsect1>
 
+ <refsect1 role="notes">
+  &reftitle.notes;
+  <warning>
+   <para>
+   The superglobals $_GET and $_REQUEST are already decoded.  Using
+   <function>urldecode</function> on an element in $_GET or $_REQUEST could
+   have unexpected and dangerous results.
+   </para>
+  </warning>
+ </refsect1>
+
  <refsect1 role="seealso">
   &reftitle.seealso;
   <para>