A group of scientists (funded by the tea industry) reported to the American Society for Microbiology that tea seems to reduce tooth decay. Volunteers in the program "swished either black tea or lukewarm water" in their mouths. Their saliva was then analyzed. It showed that those who had swished the tea had less of the tooth-decaying bacteria. The tea seems to inhibit its growth and reduces its tendency to form clumps. The tea-drinkers saliva also contained less enamel-eroding acid. Previous studies had shown that green tea helped to prevent cavities. Of course this is without the addition of sugar and honey [Darn!]
This is an excerpt from an article in Time Magazine (June 2001)