Beaumont, Texas dentist Dave Carpenter recommends throwing out your toothbrush immediately after a cold.
“… A toothbrush should be replaced every three months especially after any upper respiratory infection,” Carpenter said. Beaumont said that a more a frugal alternative is to use a dishwasher to disinfect a toothbrush.
Germs like a cold virus can live on a toothbrush up to 48 hours. Studies have also found that a toilet flush can spray up to 6-feet, festering germs throughout the bathroom including on an exposed toothbrush.