Accidentally biting your cheek while eating can cause the formation of a sore in the mouth. If you have a mouth sore because of biting your cheek, there’s nothing much to worry about. But what about a mouth sore that is filled with blood? Should you be worried? A blood blister in the mouth may give you a good reason to stress over, but these sores are usually benign and get better within some time.

What is a blood blister in the mouth?

A blood blister is a pocket or projection on the inside of the mouth filled with blood and other fluids. The blister has a dark red or sometimes purplish appearance. Blood blisters in the mouth form when the vessels underneath the skin crack.

Unfortunately, the blood and other fluids accumulate inside the mouth (cheek or other areas), resulting in a blood blister.

Symptoms of oral blood blisters

A blood blister may appear as a dark red bubble or bump inside the mouth that you can easily see or feel. There’s no specific place as to where these blisters may form. But usually, they develop on the soft surfaces of the mouth like the tongue, cheek, or bottom side of the lips. You may have a single sore or multiple formations at a time.

Blood blisters in the mouth can look ugly and give you painful sensations until they burst. They can make chewing or brushing your teeth a difficult chore.

Difference between a blood blister and other mouth sores

All sorts of oral sores, like fever blisters, canker sores, or blood blisters, form inside the mouth and have a red color. Here are the main differences between them:

Canker sores

If your mouth sore is a reddish bubble rather than a dark red to purple blister, you have a canker sore inside your mouth. Canker sores have a white or yellow outer layer.

Fever blisters

When fever blisters start to form, they can cause itching on the affected site. When talking about a blood blister, it can form abruptly and won’t give you enough time to prepare yourself for the upcoming problem.

The other symptoms that may come with a fever blister include inflammation of lymph nodes and fever. These sores commonly appear on the lips and lower side of the nose.

Causes of a Blood Blister in the Mouth

The following causes may contribute to the formation of a blood blister in the mouth:

  • Oral trauma
  • Chewing hard or sharp food items
  • Accidentally biting your cheek
  • Crown replacement procedure
  • Ill-fitting dentures that rub against the soft tissues of the mouth
  • Braces on the teeth
  • Usage of local anesthesia during a dental procedure that can cause a loss of Additionally, the patient may bite their cheeks or lips without feeling pain
  • Chronic diseases such as diabetes
  • Being allergic to acidic foods
  • Reduced platelets
  • Angina bullosa hemorrhagica
  • Chemotherapy drugs and radiation

Oral Trauma

Sometimes it is impossible to wait for a hot bowl of delicious soup to cool down before eating it. But if you don’t want to end up with a blood blister in the mouth, it’s wise to hold back. Other things that can cause an oral blister are damaging your mouth’s soft tissue with sharp food items, biting your cheek, or tripping and damaging your face. If you fall down, the blood blister may form right after the damage.


Acidic foods or drugs can annoy the tissues inside the mouth, resulting in blood blisters. The following are more likely to irritate your mouth, giving you oral blisters:

  • Foods or drinks with cinnamon flavoring
  • Citrus fruits
  • Mouthwash or toothpaste that contains astringents

Low Blood Platelet Count

When you undergo a dental procedure such as tooth extraction or an injury, platelets help blood clotting, necessary for healthy healing. While the absence of a blood clot can not only prolong the recovery period, it can also increase the chances of a dry socket.

A person may have reduced platelets, known as thrombocytopenia, due to several factors such as pregnancy or specific drugs like antibiotics or anticonvulsants. It can also happen because of Immune thrombocytopenic purpura (ITP). Specifically, ITP is a bleeding abnormality in which the immune system destroys platelets.

Blood blisters in the mouth can also occur due to thrombocytopenia. As compared to men, women are more prone to this disorder.

Angina Bullosa Hemorrhagic

Angina bullosa hemorrhagica (ABH) is a rare disorder that can also cause a painful blood blister to form on the mouth’s soft tissues. It happens when bubbles of blood form in the oral cavity. These sores appear dark red or purplish and occur suddenly in the mouth. They only last a few days and then rupture themselves while a person is chewing food.

Once these oral blisters burst, they heal quickly and don’t leave any scars on the inside of the mouth. These mouth lesions won’t cause much discomfort, but some people may experience mild pain on the affected site. A blood blister can develop at any site inside the mouth, but ABH sores mostly appear on the soft palate.

Visit your dentist or doctor if:

  • You have an abnormally large blister that’s making breathing or swallowing difficult
  • It’s been more than a week, and the sore isn’t healing on its own
  • You have extremely painful blisters that are making your daily routine miserable.
  • The mouth blisters keep coming back
  • An infected blister that is warm to the touch has red tissue around it, and pus is oozing out of it.
  • You have poorly-fitted dentures or braces that cause blood blisters in your mouth. Ask your dentist to adjust them, so they don’t cause more damage.

Blood blisters in the mouth: treatment

It is easy to manage most mouth sores with simple home remedies. If you have a blood blister in your mouth, try these treatments:

The icy way

Applying ice to a blood blister in the mouth can reduce swelling and discomfort. And if you apply the ice right after an oral trauma, the blister may not even form.

If you want to ice a blood blister in the mouth, hold the ice cube on the sore for 7-10 minutes and repeat it multiple times a day. To halt the bleeding, you can also apply mild pressure on the affected site. To add some flavor to the remedy, you can use a frozen popsicle.

Cucumber slices

Cucumbers contain a chemical named silica that is good for the healing and regrowth of skin. To heal a blood blister in the mouth, a person can hold a cold piece of cucumber on the affected area 2-3 or more times a day. To get rid of mouth sores, one can also drink cucumber juice.

Witch hazel

Witch hazel is an effective home remedy to minimize pain and dry up mouth sores. It can also help lower the swelling.

To use witch hazel to soothe a blood blister in the mouth:

  1. Soak the cotton swab in witch hazel and apply it to the sore.
  2. Keep your mouth open for a few minutes so the witch hazel can dry fully.
  3. Repeat this remedy multiple times a day until the lesion gets better.

For some individuals, witch hazel can cause slight allergic reactions. To check if you’re allergic or not, dab the witch hazel on a small non-sensitive area. If you don’t experience an allergic reaction after 24 hours, you can use it on the blister.

Chamomile tea

Chamomile tea is a tasty solution to soothe oral blisters. If you have a blood blister in your mouth, drink a cup of chamomile tea to get rid of the pain and help to heal.


To use turmeric to soothe the sore, make a balm by mixing a teaspoon of turmeric with honey. Apply this paste several times a day to the mouth blister.

Preventing mouth blisters

Oral sores can be an unsightly and painful experience.

To help heal a blood blister in the mouth and prevent it from recurring, you can:

  • Avoid spicy and salty foods that can irritate the blood blister in the mouth
  • Remove dentures till the sore gets better
  • If you suspect dentures or braces are the cause, visit your dentist
  • Don’t pop the blister as it can delay healing and increase infection risk
  • Eat only soft and cold foods until the blister heals
  • Take OTC pain relievers to ease the pain
  • Visit a doctor or dentist if the blisters reappear or are large


A blood blister in the mouth can occur due to several reasons, and they will heal within a week or two. Most of them are harmless, but you can make them go away quicker using home remedies such as cucumber slices, ice cubes, or turmeric paste.

Sometimes, a kidney failure or reduced platelet levels can cause blood blisters in the mouth, and you’ll have to consult a physician.