Canker Sore

If human beings voted their three most common diseases, canker sore would definitely be shortlisted. People of almost all ages will have the disease, and it may appear throughout the year, and there could be no escape. Canker sores, also known as “mouth ulcer”, are unlikely to be life-threatening, but seriously affect the quality of our life. The occurrence of canker sore has closely something to do with the immune system and endocrine system of the human body, and it is impossible to cure canker sores completely. Therefore, it is necessary for us to fully understand the pathogenesis and preventive measures of canker sores, so as to greatly reduce the incidence of canker sores.

What Is a Canker Sore?

Cankers sores, also known as aphthous ulcers or aphthous stomatitis, are small pitted lesions (sores) that occur inside of the mouth. 【1】They are not contagious.

Canker Sore

What are the symptoms of canker sores?

Canker sores appear inside of the mouth as round or oval sores typically with a raised border and yellow, gray, or white center. Canker sores typically develop on the following parts:

  •  On the top surface of the tongue and the tips of the tongue
  •  Underneath the tongue and on the floor of the mouth
  •  On the inside of the cheek or lip
  •  On the gum tissue

  One to two days before the appearance of the lesion, there may be a localized burning or tingling sensation inside the mouth. 【2】What’s worse, there are certain problems in diet. Meanwhile, there will be a series of systemic reactions such as headache, constipation, fatigue, irritability and lymphatic enlargement, which may even affect language function, and there is a potential risk of cancer.

How long do canker sores last?

Canker sore is cyclical and recurring, and usually heal on their own within five to seven days. However, if the pain is severe, it is necessary to take medical treatment.

What causes canker sores?

While we don’t know exactly what causes canker sores, we have identified several triggers. These include:

 Oral hygiene is not up to standards.

  Poor oral hygiene generates a very poor oral environment, which leads to the accumulation of bacteria and hazardous substances, thus resulting in infection. Improper brushing or toothbrush too hard may damage the oral mucosa and cause canker sores.

 Digestive system disease and disorders

  About 30% of patients have digestive system diseases such as gastroenteritis, abdominal distension, indigestion, constipation.

 Various nutritional deficiencies

  Patients with canker sores generally have insufficient intake of certain nutrients, including iron, zinc, folic acid, and vitamins B1, B2, B6 and so on.

 A weak immune system

  Whether the patient has a low innate immunity or a weakened immunity due to  improper diet and irregular lifestyles, which causes their immune system can’t tell the difference between healthy body tissue and antigens, thus leading to tissue damage and inducing canker sores.


  Factors such as pressure from social and family, enormous mood swings, poor sleep quality and mental stress can also induce canker sores.


  Canker sores also have hereditary characteristics. For example, when both parents have recurrent oral ulcers, the possibility of developing the disease of their children is 80% to 90%; however, if only one parent has the disease, there is a 50% to 60% possibility.

 A minor mouth injury

  A minor mouth injury such as a dental injury, biting your cheek, or wearing poorly fitting dentures is also an important cause of canker sores. Canker sores formed by this reason generally heal on their own about a week, and patients can inhibit the further growth of bacteria by smearing with saline.

 Other causes

  Allergies, dehydration, food sensitivities, especially to coffee, chocolate, strawberries, and spicy and acidic foods, hormonal shifts and some medications also cause canker sores.

How a canker sore is diagnosed?

Due to the lack of specific auxiliary examination indicators, the diagnosis of canker sores are mainly based on the history characteristics (recurrent, periodic, self-limited) and clinical characteristics (yellow, red, concave, pain), and generally no special auxiliary examination and biopsy.

Canker Sore vs. Cold Sore

Many types of sores affect your mouth. These sores are so similar that there is some confusion between them. However, their differences are important for treatment and prevention. This article looks at the defining qualities of cold sores.

Cold sores (oral herpes) are small, painful blisters. They are mostly found around the lips. Over the course of a week to 10 days, the typical process of cold sores are erupt, break open, crust over and heal. Most cold sores are caused by the herpes simplex virus 1 (HSV-1). They can also be caused by HSV-2. But that type’s more often seen in genital herpes. Both HSVs are highly contagious. They are most contagious through an active sore. But herpes can be transmitted even when you do not have sores. 【3】It is possible to get an oral herpes infection through sexual activity. But HSV-1 is more often picked up in childhood. For example, a child can get it from a parent’s kiss. You can also get oral herpes from infected objects like eating utensils and razors.Once you are infected with a herpes virus, it stays in your body forever. It may then cause outbreaks from time to time. Antiviral medications can suppress the virus and help prevent outbreaks. 

In a word, cold sores are small, painful, contagious sores on the lips. They are caused by a herpes virus. You can’t get rid of the virus, but medications can help prevent breakouts. 【4】

 Canker SoreCold Sore
LocationInside mouthAround lips
CausesVarious triggersHSV-1, HSV-2
QualitiesWhite with red border, painfulBlister-like, painful

Canker Sore Treatment

 Home remedies for canker sores

  Obviously, managing any possible triggers is a good place to start. Beyond that, you can try starting with some home remedies to reduce pain and help healing along.

Salt Water Rinse

Never put salt directly on an ulcer. Instead, make a saltwater solution 【5】 by mixing one teaspoon of salt in one cup of warm water. Swish it in your mouth or gargle it for about 30 seconds, then spit it out. Though it may sting at first, the benefits are worth it.

Baking Soda Paste

Mix baking soda 【6】 with a small amount of water until it thickens. Put the paste on your canker sores. Repeat as often as needed while your mouth heals.

Hydrogen Peroxide Solution

Mix one part hydrogen peroxide with one part water. Dab the solution on your canker sore with a cotton swab. Never swallow the hydrogen peroxide solution.

Woman with gum inflammation, closeup


Some studies have found that honey has healing properties 【7】 for canker sores. Applying honey to each sore several times a day can help reduce the number of days of pain and ulcer size and redness.

Coconut Oil

Coconut oil contains lauric acid, which can help fight some harmful bacteria in the body. Daily swishing with about a tablespoon of this oil, a practice known as oil pulling 【8】, may help reduce bacteria in the mouth and aid the healing process.

Alum Powder

Research has shown that alum can decrease canker sore size and reduce pain. To use alum, create a paste by mixing a pea-sized drop with a drop of water. Then, apply the mixture directly to each canker sore and let it sit for at least one minute before rinsing with water. Do this daily until you see results.

Apple Cider Vinegar Rinse

Another antibacterial household staple, apple cider vinegar,【9】 can be used in a rinse to help heal your canker sores. Mix a teaspoon of the vinegar into a cup of water. Swish the solution around your mouth for up to a minute. Then spit and rinse your mouth thoroughly. 【10】

 Prescription therapies for canker sores

Prescription medication may be necessary for treating persistent or severe canker sores that have gotten infected. These include topical steroids like Lidex (fluocinonide), antacids like Carafate (sucralfate), or oral steroids like Decadron (dexamethasone). 【11】

Canker Sore Prevention

 Pay attention to oral hygiene

  Pay special attention to oral hygiene and good oral care, postprandial must use toothpicks to remove food residue, and ground mouthwash, dental caries and oral reduce secondary infection. However, step up the professional cleaning schedule if you know you tend to be lax about home care.

 Develop good routines and habits 

   Canker sores can be effectively prevented if you choose healthy lifestyle, such as eating balanced diet, maintaining adequate sleep, avoiding staying up late and fatigue for a long time, avoiding irritability, nervousness and other negative emotions, and adhering to physical exercise.

 Get rid of eating acrimony excitant food

  In order to effectively reduce the stimulation of food on the oral mucosa, you ought to eat more fresh fruits and vegetables to supplement the vitamins needed by the human body. You should avoid eating spicy food such as fried food, pickled food and hot pot, and develop the habit of light diet. You should also avoid eating too cold, hot, and hard food, try to drink less and smoke less, which can prevent the oral mucosa from being damaged by external factors.

 Drink plenty of hot water

  Drink plenty of boiled water, and you can often soak in water with traditional Chinese medicines that clear away heat and fire, such as honeysuckle, chrysanthemum, dandelion, gardenia, which can effectively inhibit the rise of virtual fire in your body, so as to achieve the purpose of clearing heat and detoxifying.

  In conclusion, canker sores can be uncomfortable and make it difficult to eat, or even talk. Although most of the time canker sores do not need to be treated, some may benefit from a topical numbing agent, antiseptic mouthwash, changes in diets, and oral or topical steroids. 【12】