How to Block Spam Emails on Your Inquiry Form Without Using Captcha?

Just out of curiouity, why is captcha out of the question?

Are we talking about a wordpress site or regular html built site? If you have a wordpress site than look for a plugin called WP-SpamShield which is by far the best I've found to date. And if you're looking for a html technique that blocks automated bots than check out this css/javascript solution link: http://nfriedly.com/techblog/2009/11...hout-captchas/

Here is another solution that uses only php and css: http://www.returnondigital.com/blog/...-using-captcha

Here is another html/css/php form taken from a forum post:
The Form
<form method="post" action="">
<input type="text" name="your_name" value="" required />
<input type="email" name="your_email" value="" required />
<input style="display:none;" type="text" name="unwantedidiots" value="" />
<input type="submit" value="Send"/>
</form>

The Php on the top of the page or in the processor page
<?php
if($_POST['unwantedidiots'] != '') {
echo 'Sorry, we don\'t like spammers here!';
} else {
// Process the the form
}
?>

Then you just style it how you want with css. Hope this helps.

Keep in mind that nothing except due diligence will stop humans from posting spam and there are businesses out there who hire workers to post spam every day.

Go to plugins and click on add plugin or new one, review the results that come up. Many don't need captcha.