How To Get Rid of Canker Sores Fast

That little sore you just can't ignore

It doesn’t take much for a canker sore to get your attention, and once it’s there, it’s hard to ignore.

The good news is that even though canker sores don’t go away instantly, there are a few simple things you can do to feel better quickly. The right combination of care can calm irritation, take the edge off the pain, and help your mouth heal without it dragging on longer than it needs to.

First things first: Is it a canker sore?

Before jumping into treatment, it helps to know what you’re dealing with.

A canker sore, also called an aphthous ulcer, is a small, shallow ulcer that forms inside the mouth. You’ll usually find it on the inner cheeks or lips, under the tongue, or along the gums. It often appears with a white or yellow center and a red border. Cankers also tend to feel more painful than their size suggests.

Canker sores are often mistaken for cold sores, but they’re not the same.

• Canker sores develop inside the mouth and are not contagious
• Cold sores appear outside the mouth, usually on the lips, and are caused by a virus

If it’s inside your mouth, it’s likely a canker sore.

While they can feel random, canker sores are often triggered by things like irritation, stress, or even certain foods. We’ll come back to that in a moment, but first, let’s focus on how to get relief quickly.

How to get rid of canker sores fast

If your goal is to feel better quickly, the focus should be on reducing irritation, protecting the sore, and helping your body’s natural healing process along. Some remedies consistently stand out because they’re simple and really do help to calm irritation and promote faster healing. Here are a few worth trying out:

Saltwater rinse: Your first step for faster healing

A saltwater rinse is often the easiest place to start, and it’s surprisingly effective. Warm saltwater helps reduce inflammation and keeps the area clean, which promotes healing and lowers the risk of further irritation.

How to use it:

• Mix 1 teaspoon of salt into a cup of warm water
• Swish gently for 15 to 30 seconds
• Repeat 2 to 3 times per day

It’s simple, but many people notice improvement within a day or two.

OTC topical treatments: Fast relief when you need it

If the soreness is getting in the way of eating or talking, over-the-counter topical treatments can help almost immediately. These gels or pastes are designed to numb the area and create a protective barrier over the sore, so it’s less exposed to irritation throughout the day.

What to look for:

• Benzocaine or similar numbing ingredients specifically made for oral use
• Canker sore specific protective coatings that shield the sore

Both of these options can be found in most well-stocked pharmacies. Apply as directed, especially before meals, to make things more comfortable.

Honey: A gentle, natural option

Honey is more than just a home remedy. Its natural antibacterial and anti-inflammatory properties can often help soothe irritation. Some studies suggest it may also support faster healing and reduce discomfort.

How to use it:

• Apply a small amount directly to the sore
• Repeat 2 to 3 times per day

It’s a simple, low-risk option if you prefer a more natural approach.

Hydrogen peroxide rinse: Use sparingly

A diluted hydrogen peroxide solution can help keep the area clean and reduce bacteria around the sore, which may help prevent further irritation. The key here is to keep it gentle and avoid overuse.

How to use it safely:

• Mix equal parts 3% hydrogen peroxide and water
• Apply with a cotton swab or use as a light rinse
• Use once daily for a short period if needed.

NOTE: Use this rinse sparingly and only for a short period, as overuse can irritate the tissue and potentially slow healing.

Reduce irritation: The step that makes everything else work better

This is the part people often overlook, but it’s just as important as any treatment. If the sore keeps getting irritated throughout the day, healing will take longer, no matter what you apply. If you’re trying to figure out how to get rid of a canker sore in 24 hours, this step can make the biggest difference in how quickly you feel relief.

Until the canker sore is gone, it helps to avoid:

• Acidic foods like citrus and tomatoes
• Spicy or heavily seasoned meals
• Crunchy foods that can scrape the area
• Alcohol-based mouthwashes

Switching to softer, milder foods and using a soft-bristled toothbrush can help the area heal more comfortably and efficiently.

Why canker sores happen in the first place

Canker sores don’t have a single cause. Instead, they tend to appear when a few different factors come together. Common triggers include minor mouth injuries, like biting your cheek or brushing too aggressively, as well as stress or lack of sleep. Certain foods, especially acidic or spicy ones, can also play a role.

There’s also a connection to underlying factors like vitamin B12 deficiency, as well as low iron or folate levels. For some people, toothpaste ingredients like sodium lauryl sulfate (SLS) may increase sensitivity and trigger sores.

If you frequently get canker sores, it may be helpful to look for patterns rather than treating each one individually.

Can you get rid of a canker sore in 24 hours?

No. There's no reliable way to fully heal a canker sore in 24 hours. But you can significantly reduce pain, limit irritation, and prevent it from worsening within that time. In most cases, it’s less about eliminating the sore instantly and more about managing it well so it doesn’t disrupt your day.

What the healing timeline usually looks like

Most canker sores are self-limiting and tend to heal on their own within 7 to 14 days.

In the first couple of days, you may notice a slight tingling or sensitivity before the sore fully forms. Discomfort usually peaks around days three to five, when the ulcer is most visible and tender. From there, things typically begin to improve, with pain easing over the next few days as the tissue gradually heals. By the end of the second week, most sores have resolved completely.

When it’s worth checking in with your dentist

Canker sores are usually harmless, but there are times when it’s worth getting a professional opinion. See your dentist if:

• A sore lasts longer than two weeks
• Sores occur frequently or in clusters
• The sore is unusually large or severe
• You have a fever or difficulty eating and drinking

Recurring sores can sometimes point to issues that are worth addressing. Taking a closer look early can help ensure there’s nothing underlying and keep your oral health on track. 

A simple approach to prevention

If canker sores are a recurring issue, small changes can go a long way.

Switching to an SLS-free toothpaste, maintaining a consistent oral hygiene routine, and being mindful of food triggers can all help. Managing stress and addressing nutritional gaps, especially B vitamins, may also reduce how often they occur. And of course, consider booking checkups with your dentist and doctor to look for any possible health issues that could be causing your canker sores.

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