People take antibiotics to wipe out the bad bacteria causing an infection.

There are not enough good bacteria and too many bad bacteria.

"The first thing we discovered was that within plaque, there are what you'd call good bacteria and bad bacteria," he said.

These ingredients are tough on the body's defenses against bad bacteria.

When you take an antibiotic, it kills both good and bad bacteria in your body.

Good and bad bacteria will grow and thrive in our mouths no matter what.

But bad bacteria would go nowhere after getting a foothold in an initial infection.

Many things in food can irritate your stomach - not just bad bacteria.

These are the bad bacteria that eat away bone and cause the premature loss of teeth.

Research has shown that the "bad bacteria" which can eat bone recolonize at about 90 days after a professional cleaning.