An email is created that includes one or more destination email addresses, plus historical information regarding previously exchanged emails. Before sending this email, each of the destination email addresses is checked against the email addresses in the historical information and, if a destination email address (or the domain name of that destination address) is not found in the historical information, then a warning is displayed to alert the user to the fact that this historical information may be sent to an unintended recipient. In response to this warning, which may include a list of unapproved destination email address, the user may approve a previously unapproved destination email address, change the unapproved destination email address to one that has been previously approved, or enter a new distribution email to be substituted for the unapproved one. When creating the email, the user may also specify other approved email addresses.