diff --git a/reference/pcre/functions/preg-replace.xml b/reference/pcre/functions/preg-replace.xml
index 47849dd742..0ef9f6a748 100644
--- a/reference/pcre/functions/preg-replace.xml
+++ b/reference/pcre/functions/preg-replace.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.22 $ -->
+<!-- $Revision: 1.23 $ -->
 <refentry id="function.preg-replace">
  <refnamediv>
   <refname>preg_replace</refname>
@@ -83,6 +83,17 @@
        <literal>$1</literal> backreference, leaving the <literal>1</literal>
        as a literal.
       </para>
+      <para>
+       When using the <literal>e</literal> modifier, this function escapes
+       some characters (namely <literal>'</literal>, <literal>"</literal>,
+       <literal>\</literal> and NULL) in the strings that replace the
+       backreferences. This is done to ensure that no syntax errors arrise
+       from backreference usage with either single or double quotes (e.g.
+       <literal>'strlen(\'$1\')+strlen("$2")'</literal>). Make sure you are
+       aware of PHP's <link linkend="language.types.string">string
+       syntax</link> to know exactly how the interpreted string will look
+       like.
+      </para>
      </listitem>
     </varlistentry>
     <varlistentry>