Ever had a sore pain in your mouth that wouldn’t go away?

Then it’s probably canker sores!

Canker sores, also known by the names aphthous ulcers or aphthous stomatitis. These are small lesions or a type of ulcer that occurs on the inside of the mouth, tongue, lips, or throat  [1].

Canker sores appear to be very painful, especially if two are very close to each other.

Don’t worry, alum helps to cure canker sores quicker than other natural remedies.

Different Types of Canker Sores

Canker sores are round or oval with a yellow or white center and a red border [2].

They form more frequently inside some regions of the mouth such as on the tongue, the gums, inside the cheeks, or lips [2].

You may have a  tingling or burning sensation a day or two before the sores appear [2].

There are several types of canker sores such as:

Minor Canker Sores

Minor canker sores affect more than 80% of canker sore sufferers and are usually:

  • Tiny (less than 1 cm in diameter)
  • Oval with red edges
  • Heals in about a week
  • Does not cause scarring

Major Canker Sores

Major canker sores are less common that affect approximately 15% of canker sore sufferers. It is very painful when compared to minor canker sores and is usually:

  • Larger in shape (over 1 centimeter in diameter)
  • Appear to have defined borders but may have irregular edges when they’re very large
  • It takes about 2-6 weeks to heal
  • Leaves extensive scarring

Herpetiform Canker Sores

This form of a canker sore is very uncommon. It occurs in less than 5% of people with canker sores, and these canker sores are usually:

  • Pinpoint in size
  • Occur as clusters of tiny ulcers (generally less than a millimeter) to form larger ulcers
  • Heals in about one to two weeks
  • Does not cause scarring

Causes of Canker Sores

A study found that aphthous stomatitis affects approximately 20% of the population [3].

The cause of canker sores is still unclear. Too much acid in one’s diet, stress, and vitamin deficiencies may cause canker sores [1].

The cause of aphthous stomatitis is idiopathic and multifactorial. But it more likely involves activation of the cell-mediated immune system [3].

The exact cause of canker sores is unknown, but several factors link to the cause of it such as:

  • local trauma
  • viral infection
  • emotional or physiological stress
  • allergy or sensitivity
  • toxin exposure (nitrates in drinking water)
  • menstruation
  • Malabsorption
  • Enteropathy
  • mouth injury
  • hormonal fluctuation

An aphthous ulcer is known to be more prevalent in nonsmokers and smokers who quit. But, it is less frequent in individuals with good oral hygiene practices [3].

How Does Alum Treat Canker Sores?

The usage of alum powder for treating canker sores is famous for centuries. It has many other tremendous benefits. Alum has aluminum sulfate, the water of hydration, and the sulfate of another element [4].

Most alums have an astringent and acidic taste [4]. Alum, in general, appears as a colorless, odorless, white crystalline powder [4]. Due to their significant drying effect, alum helps to treat canker sores [5].

The astringent property that alum own helps to shrink or constrict body tissues [5].

By applying alum to the area containing canker sore, the infected tissue in that area shrinks. It causes a decrease in pressure due to swelling and the pressure around the nerves in the affected area [5].

Along with its purpose to treat canker sores, alum powder is often used to preserve food and pickled vegetables and maintain the crispness of vegetables and fruits.

Read More: 7 Best Essential Oils for Bladder Spasms Natural Remedy

Home Remedies to Treat Canker Sores Using Alum

1. Alum Block for Canker SoreAlum Block

Alum tastes bitter and will sting upon immediate application. But this is a common home that many people use.

How to use alum block:

To prepare this remedy, you will need an alum block, one to two teaspoons of water, a mortar, and a pestle.

Break the alum block into small pieces and make them into a powdered form using mortar and pestle. Take one to two teaspoons of the powder and add teaspoons of water to make a paste. Apply the alum paste to the affected area, wait a few minutes and spit it out.

But, be careful not to swallow it

2. Alum Powder For Canker SoreAlum Powder

You can use alum powder directly on the affected area.

Here is a simple method of using alum powder:

Take 1 teaspoon of alum powder and apply it to the sore. Keep it there for a few minutes and wash it. Make sure to wash it thoroughly to prevent it from being swallowed.

3. Alum Mouth Rinse for Canker Sore

Alum mouth rinse is a useful mouth rinse prepared at home.

Learn how you may prepare alum mouth rinse:

You will need a cup of water, half a teaspoon of crystal salt, and ¼ tablespoon of alum powder.

Boil a cup of water with crystal salt. Once it’s dissolved, add alum powder to it. Let it stand until it cools down. Use this mouthwash and rinse 2 to 3 times a day for best results. Although you will feel a burning sensation in the beginning, this drug will cure your problem.

Are Canker Sores and Cold Sores the Same?

Canker sores and cold sores are not the same.

The reason behind cold sores is a virus named herpes simplex virus (HSV-1).  It is more contagious when compared to canker sores.

People mistook them for the same due to the appearance of both sores on the mouth. The size, shape, and location help to differentiate between the two. The sores that appear on the surface of the lip or exterior of the mouth filled with fluid is a cold sores.

But, the ones that appear within the mouth as open sores with bright red borders and yellow or white centers are canker sores. Cold sores take to heal on their own in about two to four weeks. Several antiviral creams and pills help to speed up the healing process.

Read More: 6 Best Essential Oils for Trigger Finger (Thumb Relief)

When to Seek Medical Help For Canker Sores

Canker and cold sores are common. But, it’s advisable to visit a doctor or dentist when you experience the following:

  • Difficulty in breathing or swallowing
  • Persistent or recurring sores
  • Fever
  • Intense pain
  • Very large sores
  • Sores followed by eye discomfort

Many people confuse oral cancers with canker sores. They’re not the same. If you see any irregularity or the sore takes longer than expected, visit the doctor.


Canker sores are an irritating disease where a person can’t eat spicy or salty food. It causes a burning sensation when the food comes in contact with the affected area.

By using alum powder, the symptoms and the healing process of canker sores can be reduced and healed quicker.

Using home remedies containing alum, shouldn’t be swallowed. The exact cause of it is not clear, several factors cause canker sores from stress to allergy or braces.

Canker sores are not considered contagious like cold sores as it involves a very infectious virus.

You risk passing cold sores along when you kiss someone or share utensils with other people.

For any queries, please leave a comment in our comment section below.

Read Next: 10 Essential Oils for Thyroid Nodules (With Useful Tips)