$re = '/START (.*) END/m';
$str = 'START START JIBBERISH START END END SADASDASDAD END
START START END END
START START END END
START END
START in between END
START START END START END END END START END START END START END END
START START END START END START END START END START END END';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php