diff --git a/reference/mailparse/configure.xml b/reference/mailparse/configure.xml
index e43a6a6905..312db8833d 100644
--- a/reference/mailparse/configure.xml
+++ b/reference/mailparse/configure.xml
@@ -17,6 +17,10 @@
   of &php.ini; in order to use these functions.
   &pecl.windows.download;
  </para>
+ <para>
+  It is necessary that the <link linkend="ref.mbstring">mbstring</link>
+  extension is loaded before mailparse.
+ </para>
 </section>
 
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