$re = '/\d*[.,]?\d+\s*(?:k?g|l)\b|\b(?:k?g|l)\s*\d*[.,]?\d+/mi';
$str = 'ABC 200g EFG 5,4 Kg HIL 2x20l
ABC g200 EFG kg 5,4 HIL l 20x2';
preg_match_all($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