diff --git a/reference/outcontrol/functions/ob-start.xml b/reference/outcontrol/functions/ob-start.xml
index e130c09263..b7b204a839 100644
--- a/reference/outcontrol/functions/ob-start.xml
+++ b/reference/outcontrol/functions/ob-start.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.24 $ -->
+<!-- $Revision: 1.25 $ -->
 <refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.ob-start">
  <refnamediv>
   <refname>ob_start</refname>
@@ -107,8 +107,8 @@
      <listitem>
       <para>
        If the optional parameter <parameter>chunk_size</parameter> is passed, the
-       callback function is called on every first newline after
-       <parameter>chunk_size</parameter> bytes of output.
+       buffer will be flushed after any output call which causes the buffer's
+       length to equal or exceed <parameter>chunk_size</parameter>.
        Default value 0 means that the function is called only in the end,
        other special value 1 sets <parameter>chunk_size</parameter> to 4096.
       </para>