Abstract: An anti-virus system for electronic mail messages having detection means for determining the presence of an electronic mail message and analyzing and scanning means for detecting in the electronic mail message any tags indicating the presence of operable program code, such tags and operable code are removed from the electronic message before the message is delivered to the intended recipient. Means may also be provided for separately scanning the body and attachments of the message and for quarantining either body text or an attachment that is found to contain operable code until a decision is made whether the operable code should be deleted.