$re = '/(?:BRAND3|BRAND4)[^\n]+(\n|$)/';
$str = 'Brand,Item Number,UPC,Description,RRP, Stock Level
BRAND1,BB0001,,PRODUCT 1,74.95,Low
BRAND2,BB0002,,PRODUCT 2,74.95,Out of Stock
BRAND3,BB0003,,PRODUCT 3,74.95,Medium
BRAND4,BB0004,,PRODUCT 4,74.95,Low';
preg_match_all($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