Strip out special characters in php

I have the code below:

<?php echo $fields->question; ?>

I specifically want to st开发者_如何转开发rip out any special characters that may cause an issue with php, how could I do that? Specifically "" is causing me a problem at the moment.

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<?php echo htmlentities($fields->question, ENT_QUOTES, "UTF-8")?>

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Have you tried the addslashes() native PHP function?

$foo = addslashes($fields->question);
echo $foo;

This won't strip them out, but it should prevent them from causing you any problems by escaping the quotes.