Undo sending your mail in Gmail
If you make a typo or regret sending a message, you can undo the action by enabling the “Undo send” lab. This lab will give you the option to take back a message you just sent.
To enable the lab:
- Click the gear in the top right
. - Select Settings.
- Click the Labs tab.
- Find the “Undo Send” lab and select the Enable radio button.
- Click Save Changes at the bottom of the page.
Select the amount of time you have to undo sending a message by clicking the gear icon 
, and finding the “Undo Send:” section in the General tab of your Settings.
