No one can avoid it, drinking coffee gives you bad breath.
But why does it happen?
Apparently, it has to do with the caffeine.
Maybe you have experienced this situation; you finished your second cup of coffee and your mouth feels a bit parched. According to Yahoo! Health, that's because caffeine temporarily reduces saliva which causes dry mouth.
Saliva has many jobs, one of them is to kill bacteria in your mouth. No saliva? Then bacteria breeds, and that makes for a stinky situation.
If you add milk & sugar that's like adding fuel to the breeding fire for bacteria.
Check out this video by Yahoo! Health for ways to freshen things up in that stinky mouth.