$re = '~^(?!.*(</p>)).*|\s+</p>~m';
$str = '<div>blah</div>
<p class="mb-40px"></g></svg> </a>
</li>
</ul>
</div>
</p>
<p class="mb-40px">Foarte frumos lucru
</p>
<p class="mb-40px">I love cars</p>
';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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