People know that drinking coffee can dry out your mouth and give you bad breath.

But one researcher says a cup of joe also contains substances that could be used to fight halitosis.

A team at Tel Aviv University monitored bacterial odor when coffee was combined with saliva.

"Contrary to our expectations, we found some components in coffee that actually inhibit bad breath," said Professor Mel Rosenberg. "We expected coffee would cause bad breath, but there is something inside this magic brew that has the opposite effect."

He said that if he isolates the molecule that inhibits bacterial growth, it could be used to make new kinds of mouthwash, mints and gum.

The combination of milk and coffee may be what leads many people to have startling breath after drinking, he said.

The findings were presented to members of the International Society for Breath Odor Research in Germany.