diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index f19306e7760..9bab4ec141e 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -888,6 +888,14 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       match the data type of the column.
      </para>
 
+     <para>
+      Note, a string that returns a volatile result once cast to
+      a data type, like <literal>'now'::timestamptz</literal> and
+      <literal>'now()'::timestamptz</literal>, is evaluated at table
+      creation time, while <literal>now()::timestamptz</literal> (without
+      quotes) is evaluated at data insertion time.
+     </para>
+
      <para>
       The default expression will be used in any insert operation that
       does not specify a value for the column.  If there is no default