diff --git a/reference/strings/functions/money-format.xml b/reference/strings/functions/money-format.xml
index 757cd42744..80fb458a8d 100644
--- a/reference/strings/functions/money-format.xml
+++ b/reference/strings/functions/money-format.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.12 $ -->
+<!-- $Revision: 1.13 $ -->
 <refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.money-format">
  <refnamediv>
   <refname>money_format</refname>
@@ -224,6 +224,8 @@
   <para>
    Returns the formatted string. Characters before and after the formatting
    string will be returned unchanged.
+   Non-numeric <parameter>number</parameter> causes returning &null; and
+   emitting <constant>E_WARNING</constant>.
   </para>
  </refsect1>