You brush your teeth after every meal and floss on the regular before going to sleep. But if you're not taking a few minutes out of your day to brush your tongue as well, your oral health habits need an upgrade.

"More than 700 different bacterial species live in the mouth," explains Vera W.L. Tang, D.D.S., clinical assistant professor in the department of periodontics and implant dentistry at New York University. Not all of these microbes are harmful. But when the bad ones set up shop and multiply in the crevices around the papillae, or small bumps, on the surface of the tongue, they can inflict some real damage.

How's that? Think of your tongue as a bacteria sponge, spreading bad bacteria throughout the mouth and causing problems and disease, says Barbara L. McClatchie, D.D.S., founding member of the American Academy of Oral Systemic Health and owner of Complete Health Dentistry in Columbus, Ohio. What kind of problems are we talking about here? Consider these conditions, from the gross and embarrassing to the potentially life threatening.

Bad breath is the number one problem associated with not brushing your tongue," says Steve Cook, D.D.S., owner of Austin City Dental in Austin, Texas. How it happens: The bacteria making a home on your tongue begin doing what an overgrowth of bacteria everywhere do—give off a foul stank. The odor-causing bugs tend to lurk in the back of the tongue, he adds, which is why its important to brush back there if you want to get rid of the funk.

When you don't brush your tongue, a nasty coating of bacteria, food particles, and dead skin cells called a biofilm can cover up your taste buds, leaving your sense of taste less sharp, says McClatchie. Get rid of the biofilm and your taste buds will get going again.

We're not making it up. This condition arises when the papillae on your tongue get stained from leftover food or drink particles, like coffee, and the particles are never brushed away, says Cook. That gives the entire tongue a dark, furry appearance. It's otherwise harmless, and once you start tongue brushing, it should disappear.

Medically known as oral thrush, it can happen when the bacteria levels in your mouth get out of whack—say, from not brushing your tongue—and naturally occurring yeast grows out of control. The result: white patches on the tongue, says McClatchie. An antifungal medication can cure it, and regular tongue brushing should keep it from returning.

Bacteria buildup on your tongue can spread to your teeth, causing gingivitis, or red, inflamed gums. If it's not treated, the inflammation can advance to periodontal disease, when the gums pull away from the teeth and the space in between becomes infected. Your teeth may fall out, but even more worrisome is that the chronic inflammation caused by periodontal disease is linked to a higher risk of heart attack, stroke, and miscarriage, says McClatchie.

By now, you'll probably want to grab your toothbrush and give your tongue a good scrubbing. Here's the right way to do it: Starting at the back of the tongue, gently brush toward the front, then go side-to-side. You don't have to use toothpaste, but it'll probably feel more comfortable, and the abrasiveness of toothpaste can help make cleaning more effective, says McClatchie. Do it at least once a day for a few minutes at a pop, but ideally twice, she adds.

Oh, and you've probably heard of tongue scrapers: tools found in the pharmacy dental aisle that are specially designed to remove bacteria, food particles, and other gunk from your tongue. While it's perfectly fine to use one, all you really need for effective tongue brushing is a plain-old non-tricked-out toothbrush, says Cook.