A study conducted by University of Manchester researchers finds a toothbrush can contain over 10 million bacteria including E. coli and Staph.
Prosthodontist Dr Ann Wei told Grandparents.com that in an unbrushed mouth, there can be as many germs as a dirty bathroom floor.
Your toothbrush can be contaminated by the water splashed when we wash our hands, or worse, by bacteria from an open-flushed toilet.
And if you drop your toothbrush on the floor, the five second rule does not apply.
It picks up airborne bacteria that has settled on the floor and everything else that people traipse through via their feet.