Including Perl CGI output

Well, this is my first post on this list, so here goes :-)

I have a Perl CGI script that returns a plain piece of text to me. I used 
to include this output in my documents with SSI but now I have moved to PHP 
I am not sure how to get the same result as I am not mixing two languages. 
I can include output from a PHP file using:
<?PHP require ('/xxx/xxx.php3'); ?>
But it doesn't work for Perl scripts

Has anyone get any ideas?

Thanks in advance
Adam Charnock