Is it possible to delete a mail before the recipient reads it in Gmail?

Question

I sent an unrelated mail to my boss. I want to delete the mail before my boss reads the mail. Is it possible to delete the mail before the recipient reads it in Gmail ?

Answer 1

There is an Undo Send lab which will give you an undo button as soon as you send a message. Unfortunately it won't help a past mistake, the email has already been send to the recipient's mail server.