$re = '~(?<=<errorMessage>)[^<>]+(?=</errorMessage>)~m';
$str = ' <?xml version="1.0" endcoding=UTF-8"?>
<n0:szemelyKutyaFuleResponsexmlns:prx="urn:sap.comproxy:SWP:/1SAI/TREASE1243804269AE457508F4:753" mmlns:n0="http://csajgeneratorws.tny.interfesz.kok.lo/">
<return>
<tanzakciosAzonosito>46981682-4637-49d2-bd4d-dcfff543742ed</tanzakciosAzonosito>
<erdmeny>HIBAS</eredmeny>
<errorCode>TSH08</errorCode>
<errorMessage>Azonosítószám már hozzá lett rendelve üzleti partnerhez</errorMessage>
</return>
</n0:szemelyKutyaFuleResponse>';
preg_match_all($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