You know it’s a bad habit, but did you know that it can also make you sick?

Many people have nervous habits, such as pacing or fidgeting, and although many are harmless, if you bite your nails when you’re stressed or anxious, you are actually at risk for some ailments. Texas A&M University Health Science Center experts offer five reasons why you should kick this habit.

Your nails pack a lot of dirt.

There are a lot of germs under your fingernails. Even if you wash your hands frequently, its difficult to get all the germs and dirt from under your nails. So just imagine what you’re exposing your body to whenever you give these germs and dirt free access to your mouth. Yuck. Once the germs that were under your fingernails get into your body, your chances of illness increase significantly. Be sure to wash your hands thoroughly and pay extra attention to your nails.

You can spread infection from nail to nail.

It increases risk of infection. Biting your nails increases the risk of paronychia, an infection of the nail. Symptoms of paronychia include a painful, red, swollen area around the nail, often at the cuticle or at the site of a hangnail or other injury. If the infection is bacterial, there may be pus-filled blisters at the site. Also, if you chew on nails that have warts—which are caused by a virus—and then chew on other nails, this can cause warts to spread to other areas.

Nail biting is bad for your teeth.

It’s bad for your teeth, it’s not recommended to use your teeth as tools, apart from chewing your food. Regularly biting your nails can cause your teeth to shift out of place, which can require correctional braces or a retainer. Nail biting could also cause your teeth to break or could damage your tooth enamel. The germs could also potentially infect, or cause irritation, to your gums. Also, the bacteria that is on your fingers or nails can linger in your mouth and cause halitosis, or bad breath.

Hangnails can lead to infection.

You can have more hangnails or ingrown nails if you constantly bite at your nails, chances are you’ll bite off a bit more than you expected, and when a piece of torn skin at the root of your nail appears, that’s a hangnail. Hangnails are open sores that can easily become infected. The best way to avoid the painful sores is to prevent the hangnail from forming in the first place by moisturizing regularly—and not chewing on your fingers. Most ingrown nails occur on the toenails, but biting your nails can cause your nails to grow under your skin in your fingers too. Ingrown nails can cause pain and swelling and potentially lead to infection and require surgery.

If you paint your nails, it might not be safe to put in your mouth.

There’s a risk of toxic poisoning. If gel polishes are your thing, it’s best that you kick the nail-biting habit sooner rather than later. Regular nail polishes have plenty of toxins themselves, but gel polishes have chemicals that can be harmful when ingested. Although the low amounts of toxicity likely won’t show any harmful effects right away, we don’t yet understand all of the potential long-term consequences.