diff --git a/reference/pdo/functions/PDO-prepare.xml b/reference/pdo/functions/PDO-prepare.xml
index ea299018ab..4ef54229cc 100644
--- a/reference/pdo/functions/PDO-prepare.xml
+++ b/reference/pdo/functions/PDO-prepare.xml
@@ -1,5 +1,5 @@
 <?xml version='1.0' encoding='iso-8859-1'?>
-<!-- $Revision: 1.4 $ -->
+<!-- $Revision: 1.5 $ -->
 <!-- Generated by xml_proto.php v2.1. Found in /scripts directory of phpdoc. -->
   <refentry id="function.PDO-prepare">
    <refnamediv>
@@ -22,6 +22,8 @@
      <function>PDOStatement::execute</function> method. The SQL statement can
      contain zero or more named (:name) or question mark (?) parameter markers
      for which real values will be substituted when the statement is executed.
+     You cannot use named and question mark parameter markers within the same
+     SQL statement.
     </para>
     <para>
      Calling <function>PDO::prepare</function> and <function>PDOStatement::execute</function>