diff --git a/reference/pdo/pdostatement/execute.xml b/reference/pdo/pdostatement/execute.xml
index 90f812e58a..d83444d3dc 100644
--- a/reference/pdo/pdostatement/execute.xml
+++ b/reference/pdo/pdostatement/execute.xml
@@ -35,6 +35,7 @@
       <para>
        An array of values with as many elements as there are bound
        parameters in the SQL statement being executed.
+       Ale values are treated as <constant>PDO::PARAM_STR</constant>.
       </para>
       <para>
        You cannot bind multiple values to a single parameter; for example,