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Dentists Reveal How to Get Rid of Canker Sores Fast + What Remedies Actually Make Them Worse

Hydrogen peroxide may be a medicine cabinet staple, but it can be bad news for canker sores

What starts as a subtle tingle or burning in your mouth can signal something more painful on the horizon: a pesky canker sore. For some, the ulcers are just a mild annoyance. But for many of us, they trigger pain and irritation that can make everyday activities like eating a chore. And when that happens, you want to know how to get rid of canker sores fast.

While canker sores run their course — often a week-long slog — there are home remedies and drugstore treatments that can ease symptoms and encourage healing. Find out what top dentists recommend, plus the two popular remedies they say you should skip.

What is a canker sore?

Medically known as an aphthous ulcer, canker sores are small, shallow lesions that develop on the soft tissues in your mouth or at the base of your gums. ”It’s basically an inflammatory reaction in the lining inside of the mouth,” explains Cesar A. Migliorati, DDS, professor of oral medicine at the University of Florida’s College of Dentistry. “They occur in areas where the lining of the oral cavity is thinner. This includes the inside of the cheeks, the inside of the lips, under the tongue, the roof of the mouth and going towards the throat.”

Unlike cold sores, which are caused by the Herpes virus, canker sores don’t occur on the surface of your lips and they’re not contagious.

A close-up of a woman holding her lip up to reveal a canker sore she wants to get rid of fast
Panuwat Dangsungnoen/Getty

Canker sore symptoms

Before you even see them, you might feel a discomfort that hints that a canker sore is on its way. It starts as a small red spot and soon opens up into a crater-like sore. These sores, which can be round or oval, have a white or yellow center surrounded by a red outline. Small ones measure in at about an eighth or quarter of an inch, while larger ones can grow up to half an inch in size.

What makes them such a hassle? Canker sores exposes sensitive nerves that respond painfully to change, whether it’s a sip of something hot or simply moving your mouth, reveals Teresa Yang, DDS, a dentist in Los Angeles and author of Nothing But the Tooth: An Insider’s Guide to Dental Health.

Common causes of canker sores

Around 1 in 5 people will get canker sores at some point in their lives, often beginning in puberty. While canker sores aren’t caused by bacteria or viruses, what exactly triggers them is still a bit of a puzzle, Dr. Yang says. Different things can set them off for different people. Often to blame:

1. Injury or irritation

Accidentally biting your cheek, eating foods that are too hot, spicy or acidic and even brushing your teeth too hard can cause these sores to form, notes Dr. Yang. However, some folks seem to get them more easily and have a stronger reaction to triggers, including dental procedures.

“I have a couple of patients who come into cleanings just expecting they’ll develop canker sores afterward, and they’re not exaggerating,” says Dr. Yang. “So trauma can include any kind of dental work, even brushing their teeth.” (Click through to learn how to clean your toothbrush to whisk away troublemaking bacteria.)

2. Using the wrong toothpaste

Dr. Yang says a common ingredient in toothpaste and dental products known as sodium lauryl sulfate (SLS) could trigger canker sores in some people. In fact, a study suggests that for those who often get these sores, SLS might cause them or make them worse by harming the mouth’s protective lining. If you have a sensitive mouth or frequently develop canker sores, try getting rid of your regular toothpaste in favor of one free of SLS, suggests Dr. Yang.

A wooden toothbrush with red bristles and white toothpaste against a blue background

3. Your genes

Canker sores can also run in families. If you have parents or siblings prone to canker sores, you may be more likely to get them yourself. It doesn’t mean necessarily it’s going to happen, but there’s a higher chance, says Dr. Migliorati.

4. Stress

When you’re tense, your body releases cortisol, a hormone that helps you handle stress in small amounts, Dr. Yang says. But when stress become chronic, elevated cortisol levels weaken the immune system. This can make your mouth less able to prevent minor infections or heal small injuries that can spur canker sores. (Click through to learn how to reduce cortisol easily and naturally.)

5. Your diet

For people with allergies or food sensitivities, certain foods (including chocolate and strawberries) can be canker sore triggers. Soda could be a culprit, too, suggests one study. What’s more, Dr. Yang notes that deficiencies in certain vitamins and minerals such as Vitamin B 12, iron or folic acid could lead to a greater occurrence of canker sores.

Related: Experts Reveal How to Get Rid of a Cold Sore + the TikTok Trend You Shouldn’t Try

How to get rid of canker sores fast

When painful canker sores flare up, you want to get rid of them fast. And while you can’t cure a sore overnight, you can tame discomfort while they heal.

1. Swish with saline

One of the best ways to help get rid of canker sores and encourage healing is by rinsing your mouth with a saltwater solution, Dr. Yang says. This reduces inflammation and soothes pain. Simply add 1 tsp. of salt to 1/2 cup of warm water. Swirl the mixture around your mouth for 30 seconds (then spit) once or twice daily.

A glass of water beside a spoon of sale, which helps get rid of canker sores fast

2. Try a baking soda rinse

Similar to a saltwater rinse, baking soda neutralizes the acids in your mouth to ease inflammation and pain, Dr. Yang says. Add 1 tsp. of baking soda to 1/2 cup of warm water. Swirl the mixture around your mouth for 30 seconds (then spit) once or twice daily. (Leftover baking soda? Click through to see our best baking soda hacks.)

Note: As painful as it is, it’s vital to maintain dental hygiene while nursing a canker sore, Dr. Migliorati says. If you prefer a store-bought rinse, his go-to product is CloSYS Ultra Sensitive Mouth Rinse. “This mouth rinse has no irritants,” he notes.

3. Avoid irritating food and drinks

While your canker sore is healing, you may want to skip foods that can irritate the open wound. This includes hard, crispy and spicy foods, salty snacks like pretzels, chips and nuts and citrus and acidic fruits such as tomatoes. Dr. Yang also suggests chewing on the other side of your mouth free of canker sores if possible.

4. Savor a sweet spoonful

To get rid of the pain of canker sores, try spooning up honey. It has antibacterial properties that encourage healing. Plus it’s thick texture naturally coats and protects the sores. A study in Quintessence International even found it as effective as topical corticosteroid treatments for canker sores.

A wooden honey dipper with honey dripping off of it on a yellow background
Adela Stefan/Getty

Tip: Eating soup (as long as it’s not too hot) and soft foods helps protect your mouth’s mucous membranes, too. (Click through to see more foods for healthy gums.)

5. Try lysine

Though lysine is known for treating cold sores, it can be helpful for getting rid of canker sores as well. The amino acid helps make proteins needed for healthy skin and tissues in the mouth. And a study in General Dentistry suggests taking 500 mg. of lysine daily reduces canker sores. One to try: NOW Foods L-Lysine.

6. Use a canker sore cover

To help get rid of the pain from canker sores, you can place dissolvable “covers” over the ulcers. Not only does it calm discomfort in the moment, it serves as a protective barrier against irritants that can slow healing. “Patients have reported good success with products that cauterize the canker sore, meaning turn it into a scab,” Dr. Yang explains. “Once the sore scabs over, it doesn’t hurt.”

One to try: Dentemp Canker Cover, a dissolvable tablet that can be applied to canker sores up to three times a day, as needed.

7. Consider an OTC gel

Topical anesthetics made with lidocaine or benzocaine, such as Orajel Mouth Sore Gel, dull the pain of a canker sore. They typically come in a gel or cream formula. You can apply them to canker sores with a Q-tip up to four times a day to soothe discomfort, Dr. Yang says.

Clear gel smeared on a lilac background
Anna Efetova/Getty

What to skip to get rid of canker sores

When you want to get rid of canker sores fast and encourage healing, it’s best to avoid these remedies. Why? It turns out they can actually do more harm than good!

Hydrogen peroxide

Hydrogen peroxide for canker sores is a popular DIY rinse that combines one part hydrogen peroxide with water. But research in the Journal of Periodontology suggests the medicine cabinet staple can hurt your mouth, especially if you already have a sore or injury there. Dr. Migliorati warns against using hydrogen peroxide for canker sores, since “it irritates the mouth.”

Antiseptic mouth rinses

Mouthwashes with antiseptic properties, such as Orajel Antiseptic Mouth Sore Relief, reduce the amount of bacteria in the mouth to prevent a canker sore from worsening. However, Dr. Yang does not recommend using them. “There are both good and bad bacteria in the mouth, but the antiseptic mouth rinses won’t differentiate between the two.”

Related: Dentists Say These 6 Tips Help Stop Bleeding Gums Naturally

How to get rid of canker sores fast: When to see a dentist

Canker sores aren’t usually a big health concern. Still, seeing an oral health specialist can be a good idea, especially if the pain is unmanageable or the sore has staying power, says Dr. Migliorati. They can offer stronger treatments like cortisone-based creams that help heal sores faster.

Plus, sometimes what seems like a canker sore might be something more serious, such as an autoimmune condition called lichen planus or oral cancer. That’s why it’s crucial to get persistent sores checked out, Dr. Migliorati advises. “95% of cancers in the oral cavity start right on the lining, meaning if we do an oral examination, we will see it right away,” he explains. “If you have a sore in your mouth that is not healing in a week or 10 days, it needs to be evaluated.”

A woman in a dentist chair getting her mouth examined to get rid of canker sores fast

For more ways to keep your smile healthy:

Dentists Reveal 7 Foods for Healthy Gums, Including a Sweet Treat You’d Never Expect

Dentists Say These 6 Tips Help Stop Bleeding Gums Naturally

These Easy, Surprising Self-Care Tips Can Reverse Gum Disease, Say Dentists

This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.

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