how do I suppress system messages?

[Lynette Tillner]

This is something that drives me crazy but I've not been able to find a way to stop it. 

When I log into my FreeBSD 4.6 Web Server as root, I get messages from sendmail that I can't suppress with dmesg.  They are a real pain because they even come across the screen when I'm using VI to edit files and then I can't figure out the line I was in the middle of editing, and end up doing a :q! and starting over, very frustrating because we get tons of mail and it seems like I can't do anything as root because of these messages. 

Is there a command that will suppress the messages?   I remember being able to do that when I was working on an HP-UX system but haven't figured it out under FreeBSD.

Thanks for any help!

Lynette