add_filter('the_content', 'remove_empty_tags_recursive', 20, 1);
function remove_empty_tags_recursive ($str, $repto = NULL) {
         $str = force_balance_tags($str);
         //** Return if string not given or empty.
         if (!is_string ($str)
         || trim ($str) == '')
        return $str;
 
        //** Recursive empty HTML tags.
       return preg_replace (
 
              //** Pattern written by Junaid Atari.
              '~\s?<p>(\s|&nbsp;)+</p>\s?~',
 
             //** Replace with nothing if string empty.
             !is_string ($repto) ? '' : $repto,
 
            //** Source string
           $str
);}