forcing a reload from a redirect

I have two pages, foo.php and bar.php. bar.php redirects the user to foo.php with the following code: header("Location: http://".$_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']) . "foo.php"); Normally, I want the browser to cache foo.php, it's content is fairly static. But, bar.php makes changes that will cause foo.php to change. How do I force foo.php to reload from the server whne I do this redirect? I've seen code that adds a random number as a search string on the end of the URL, but I want to avaoid that if possible. -Mike