How Long Do Canker Sores Last?

logo by Editorial Staff | Posted on July 15th, 2022

Small, painful sores that develop inside the mouth are known as canker sores or aphthous ulcers. The lesions are oval-shaped ulcers with a crimson ring surrounding a yellow-gray center.

Eating, drinking, and speaking can all be uncomfortable during a canker sore. They often disappear on their own after 2 weeks, but many over-the-counter (OTC) remedies can hasten recovery. 

canker sore

How common are canker sores?

You may be surprised to find that, according to the International Association of Oral and Maxillofacial Surgeons, 20% of the population experiences canker sores. These painful ulcerated lesions or sores might make it difficult for you to talk or chew your meals. 

Types of canker sores

Canker sores vary in appearance. Herpetiform, large, or small canker sores can all occur.


Around 80% of cases of canker sores are of the minor variety, making them the most prevalent. They can vary but most often range from ⅓ inch to ½ inch. They may also be referred to as straightforward canker sores.

Minor canker sores, despite being uncomfortable, frequently heal completely in two weeks. They can come on suddenly, frequently following a minor oral injury, or when you are continuously overworked and worn out. 


Major canker sores that are larger than ½ inch typically persist for longer than two weeks. Major canker sores frequently have uneven, weirdly shaped borders, in contrast to mind canker sores which are normally circular and symmetrical.

This particular canker sore can occasionally leave a scar. Major canker sores are typical in patients with immunosuppression brought on by chemotherapy or illnesses like HIV. Complex canker sores are another name for major canker sores. They cause 15% of canker sores. 

Herpetiform Canker Sores

Herpetiform canker sores are a collection of small lesions that frequently come together to form a single, larger sore. There may be hundreds of lesions the size of a pinhead. Canker sores with a herpetiform appearance might linger for a week to a month.

Although the herpes virus is not present, herpetiform canker sores can resemble an outbreak of the disease. They typically happen later in life, though the source is uncertain. Five percent of cases of aphthous ulcers are herpetiform canker sores. 

Symptoms of canker sores

Small lesions in your mouth are known as canker sores. They can hurt and are often tiny and white. They occasionally come in huge sizes. They show up on your gums or inside your mouth. The typical duration of a canker sore is one to two weeks.

However, large sores may persist for six weeks. You may experience a tickling, burning, or tingling feeling in the area before you get a canker sore. The sore will eventually become circular with a white or yellowish center. 

The majority of canker sores have a diameter of less than 1 millimeter. However, their diameter can reach one inch. They can last longer when larger and may have a more irregular shape. When they have healed, larger canker sores may also leave scars.

They might happen individually or in groups. Canker sores can be uncomfortable and may hinder speech or eating, especially if they are large. If the situation is more serious, you can also develop a temperature or feel generally unwell. 

Causes of canker sores

Canker sores have a variety of potential causes, although experts are unsure of their actual causes. These consist of:

  • Mouth wounds
  • Intolerance of certain foods or germs
  • Oral hygiene items using sodium lauryl
  • Sulfate
  • Low amounts of B-12
  • Low levels of folate
  • Low levels of iron
  • A bacterial infection with H. Pylori
  • Hormone adjustments
  • Excessive stress
  • Overconsumption of citrus fruits
  • Eating too many tomatoes and other acidic meals
  • Making use of non-steroidal anti-inflammatory drugs
  • Immune-system compromising conditions, including lupus and celiac disease

How to treat canker sores fast

A few over-the-counter medicines could hasten the healing process and ease any pain or discomfort. When you use these products as soon as you notice a canker sore developing, they perform best:

  • Mouthwash with hydrogen peroxide
  • Fluicinocide
  • Benzocaine

Easy ways to get rid of canker sores within 24 hours

Baking soda

A component found in every kitchen. It works incredibly well to treat a mouth sore or canker. It regulates ph and lessens inflammation. In a half-cup of water, combine one teaspoon of baking soda. After using this solution to rinse your mouth for 20 to 30 seconds, spit it out. Repeat as necessary.

Hydrogen peroxide

By releasing oxygen, a substance with modest antiseptic characteristics destroys the bacterium. Take a hydrogen peroxide solution and further dilute it with an equal amount of water. Take a hydrogen peroxide solution and dilute it with equal water. To relieve pain, dip a cotton ball in the solution and place it where needed. 


It treats a canker sore for 24 hours when in powder form. It has astringent qualities that cause the sore to dry up and the cells to contract. A pinch of alum powder should be applied lightly to the canker sore. Rinse after one minute of letting it sit. 

Saltwater rinse

Take one teaspoon of salt and dissolve it in half a cup of water. To fight infection, gulp down a small bit of this combination and gargle for 20 to 30 seconds. 


They are more effective at treating canker sores because they contain probiotics. It works against the bacteria in the stomach that is responsible for mouth sores and inflammation.

Milk of magnesia

This acid neutralizer stops the sore’s ability to spread to other regions. 

Coconut oil

Simple to find a component that fights infections and eases pain and swelling. On the sore, it may be used more than once each day.


Qualities are astringent, antibacterial, and antiseptic. Even more, the justification for adoring this vegetable. Use it as a mouthwash after boiling it in water, straining, and letting it cool. 


Chamomile contains substances including azulene and levomenol that lessen redness, swelling, and pain. 


Honey helps to reduce inflammation and bacteria. It is applied to reduce a canker sore’s size. Kids love it because of its sweet flavor. 


A blooming plant that increases immunity while healing wounds is beneficial for treating a canker sore. 

Zinc lozenges

It increases immunity and aids the body’s defenses against bacterial invasion.

Licorice flavoring

Boil two tablespoons of licorice powder in water, swish it in your mouth and then spit it out. 


The holy grail of vinegar is apple cider vinegar. Canker sores respond well to their antimicrobial effects. 

B-12 vitamin

Canker sores and vitamin B-12 deficiency are related. For prevention, regularly use vitamins. 


Place on the affected area to witness a quick reduction in discomfort and redness. However, it causes hypoglycemia, and people with diabetes should exercise caution when using it. 


Ice is a magic trick that helps the wound heal more quickly and reduces discomfort by numbing the region. 

How to prevent canker sores

There are things you may take to stop canker sores from returning when you develop them:

  • First, eat less of the stuff that makes your mouth itch.
  • Consume a healthy diet
  • Avoid toothpaste and mouthwashes containing sodium lauryl sulfate, and routinely brush your teeth and floss.
  • If you have braces, use orthodontic wax to shield your mouth. 
  • Attempt to relax more.
  • Treat any underlying issues that lead to canker sores. 

Frequently asked questions

What causes a canker sore?

A wide range of factors could cause your canker sores. For instance, you can have harmed the tissue while playing sports, brushing your teeth, or even accidentally biting your cheek. These uncomfortable sores can also be brought on by hormonal changes, such as during menstruation. In addition, these sores can be caused by food allergies (such as those to spicy or acidic foods), vitamin deficiencies, immune system deficiencies, or food sensitivities. 

Are they contagious?

Canker sores are not spreadable. Contrary to popular belief, the herpes virus does not cause canker sores, so there is one less thing to be concerned about.

How do you treat a major canker sore?

Your doctor could advise using an antibiotic mouthwash or a corticosteroid ointment if your canker sore is large and severe. Oral pain gels sold over-the-counter can also aid with symptoms. 


Aphthous ulcers, or canker sores, are uncomfortable, pitted sores in the mouth. Canker sores are related to stress, oral injuries, dietary sensitivities, vitamin deficiencies, menstruation, digestive issues, and weakened immunity, even though their exact etiology is unknown.

Therefore, treatment for canker sores is not usually necessary. However, some patients may benefit from topical anesthetics, antiseptic mouthwash, dietary modifications, and oral or topical steroids. 


Editorial Staff

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