Is there a way to retract an e-mail sent from gmail?
Sadly, that’s all there is to it. Once you send it, it’s gone. Since email is a distributed service (there’s no centralized email system for everyone), once gmail sends the email to another server (the server hosting the recipient’s email) than gmail has no control over it whatsoever. Even if you send it to another gmail address, it’s treated just the same. In corporate environments (using MS Exchange) this is different because the same server handles both ends of the email, so you can request a return (though the other person doesn’t have to accept it), or you can pray to the email gods (i.e., bribe the Exchange Admins, hint: try booze or women!) and they can make the email disappear like it was never even sent. OR better yet, they can make it look like it came from someone else :-D.