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Swollen Gums: Common Causes and When to Get Help

Swollen gums are most often a sign of gingivitis, but an abscess, a wisdom tooth coming through, pregnancy, some medicines and dentures that no longer fit can also be the cause. Here is how to tell, what helps and when swelling is urgent.

Updated September 2026·By the OHA editorial team·7 min read·How we write
Key takeaways
  • The most common cause of swollen gums is gingivitis: plaque along the gumline irritating the gums. Gentle brushing twice a day and cleaning between your teeth usually help it settle.
  • Swelling around one tooth with throbbing pain, a bad taste or a fever may be a dental abscess or an infected wisdom tooth. See a dentist urgently.
  • Pregnancy, some blood pressure, epilepsy and transplant medicines, and dentures that no longer fit can also make gums swell.
  • Swelling that spreads to your face, eye or neck, or makes it hard to breathe, speak or swallow, needs emergency care.

MedlinePlus, from the US National Library of Medicine, says gum swelling is common. Most swelling comes from plaque and settles with better cleaning, but it can also be a sign of an infection that needs treatment quickly. This page helps you work out the likely cause and links to our fuller guides.

What causes swollen gums?

Gingivitis (early gum disease)

healthdirect Australia says gingivitis is caused by plaque (a sticky film of bacteria) building up along the gumline, which irritates the gums and may make them bleed or swell. The NHS says gum disease is very common but important to get checked by a dentist.

healthdirect says gingivitis treated early is usually reversible. Left untreated, it can develop into periodontitis, a more serious form of gum disease that may be irreversible. See gum disease and bleeding gums.

A dental abscess

The NHS describes a dental abscess as a build-up of pus in the teeth or gums caused by an infection. Symptoms include intense pain, a bad taste, a swollen face or jaw and a high temperature. The NHS says it will not go away on its own and needs urgent treatment by a dentist. See dental abscess.

A wisdom tooth coming through

healthdirect lists wisdom teeth coming through among the causes of toothache and gum swelling. The NHS says that when a wisdom tooth does not have enough room, it may be partly covered by the gum, which can cause pain and swelling and an infection of the gum called pericoronitis.

The Better Health Channel (Victoria) lists signs of this infection: red, inflamed gum near the tooth, facial swelling, pus, swollen glands under the jaw, difficulty opening the mouth and swallowing, fever and bad breath. It says the infection may keep coming back if a problem tooth is not removed. See wisdom teeth.

Pregnancy

The American Dental Association (ADA) says some people develop pregnancy gingivitis, which causes swollen, tender gums that may bleed a little when you brush or floss, because higher hormone levels change how the gums react to plaque. The Better Health Channel says it is most likely in the second trimester.

The ADA also describes pregnancy tumours, red overgrowths on the gums that bleed easily. Despite the name, it says they are not cancer and usually disappear after the birth. See pregnancy and oral health.

Medicines

The Better Health Channel says some medicines can make the gums swell, become inflamed or overgrow (called gingival hyperplasia), and that swollen gums are harder to clean, which raises the risk of gum disease. Its examples are some blood pressure and epilepsy medicines, immunosuppressants (medicines that damp down the immune system) such as ciclosporin, and oral contraceptives in some people. MedlinePlus lists gum overgrowth as a side effect of phenytoin, an epilepsy medicine.

If you think a medicine is the cause, MedlinePlus says to talk to your doctor about changing it, but never stop a medicine without talking to them first. The Better Health Channel says your doctor may be able to adjust the dose or switch medicines, and a dentist can carefully trim overgrown gum. See medicines that affect your mouth.

Dentures and other dental appliances

MedlinePlus lists poorly fitting dentures or other dental appliances as a cause. The NHS says dentures may loosen as your gums and jawbone change shape with age, and advises not wearing them overnight unless your dentist recommends it, because trapped food raises the risk of gum infections. healthdirect says to see your dentist or dental prosthetist (a denture specialist) if your mouth is sore or you have swelling, bleeding gums or ulcers, as your dentures may need adjusting. See dentures and looking after your mouth in older age.

An injury to the mouth

healthdirect says a mouth injury, such as a fall, a blow to the face or biting on something hard, can make the lips or gums swell. It suggests a cold compress (an ice pack wrapped in a cloth), and says to see a dentist after any dental injury, because you might not see all the damage. See dental emergencies.

Other causes

MedlinePlus also lists food caught under the gums, sensitivity to a toothpaste or mouthwash, infection by a virus or fungus, malnutrition, and scurvy (a severe lack of vitamin C). Two examples of infection:

  • Cold sore virus. NHS inform (Scotland) says a first infection with the herpes simplex virus, most likely in children under 5, can cause swollen, irritated gums with small, painful sores and a fever. See cold sores.
  • Oral thrush, a fungal infection, can cause sore gums, according to the NHS. See oral thrush.

healthdirect also lists a mouth ulcer and, rarely, mouth cancer.

What can you do at home?

  1. Keep brushing, gently. healthdirect says to brush twice a day with a soft toothbrush and fluoride toothpaste, and to keep brushing and flossing even if your gums are bleeding or inflamed. The NHS says to clean between your teeth every day.
  2. Ease the pain while you wait for a dentist. healthdirect suggests soft foods, avoiding very hot or cold drinks, resting with your head propped up and a cold compress against your face. It says a salt-water gargle may help mild toothache (do not swallow it).
  3. Painkillers. healthdirect says to ask your doctor or pharmacist about paracetamol or ibuprofen and to follow the instructions on the packet. It says antibiotics are usually not used for toothache unless there is a clear infection.
  4. Check your products. If a toothpaste or mouthwash seems to be irritating your gums, MedlinePlus suggests switching toothpaste and stopping the mouthwash.
  5. Do not smoke (NHS).

Home care helps gingivitis, but it does not treat an abscess. The NHS says an abscess needs a dentist.

What will a dentist do?

healthdirect says your dentist will examine your mouth and may take an X-ray. For gum disease, the dentist cleans your teeth and gums to remove plaque; a problem tooth may need a filling, a crown, root canal treatment or removal. The NHS says a dentist treats an abscess by draining the pus. MedlinePlus says you may be asked about your diet and medicines.

When to see a dentist
  • Your gums are painful and swollen, or bleed when you brush or eat hard foods (NHS).
  • Toothache and gum swelling last more than 2 days or do not improve with pain relief: healthdirect says see a dentist as soon as possible.
  • You have gum swelling with a fever over 38°C, pain when you bite, a bad taste, swelling in your cheek or jaw, or trouble swallowing (healthdirect).
  • A wisdom tooth is causing problems (Better Health Channel).
  • Your gums are sore or swollen under dentures, or your dentures slip or no longer fit (healthdirect, NHS).
  • Changes to your gums last longer than 2 weeks (MedlinePlus).
Get help urgently
  • UK: the NHS says ask for an urgent dentist appointment or get help from NHS 111 if you think you have a dental abscess, or if you have gum disease with very sore and swollen gums, loose teeth, ulcers or red patches, or a lump in your mouth or on your lip. Do not go to a GP surgery for an abscess, as a GP cannot give dental treatment.
  • UK emergencies: the NHS says call 999 or go to A&E if you are finding it hard to breathe, speak or swallow, have a swollen or painful eye or sudden eyesight problems, a lot of swelling in your mouth, or difficulty opening your mouth. Do not drive yourself.
  • Australia: healthdirect says get emergency medical care if toothache or gum swelling causes problems breathing or speaking, or swelling around your eye or neck. After a mouth injury, call triple zero (000) or go to an emergency department if you have trouble breathing, talking or swallowing, a lot of blood going down your throat, or a very swollen mouth or tongue.
  • Elsewhere, call your local emergency number for any of these signs.

Frequently asked questions

Will swollen gums go away on their own?

It depends on the cause. healthdirect says gingivitis is usually reversible if treated early by removing the plaque, so better brushing and cleaning often help. An abscess is different: the NHS says it will not go away on its own. MedlinePlus says to contact a health professional if changes to your gums last longer than 2 weeks.

Should I brush if my gums are swollen and sore?

Yes, gently. healthdirect says to keep brushing and flossing even if your gums are bleeding or inflamed, using a soft toothbrush and fluoride toothpaste.

Why is my gum swollen around just one tooth?

Swelling in one place can have several causes, including a dental abscess (NHS), a wisdom tooth coming through (healthdirect) or food caught under the gum (MedlinePlus). A dentist can find the cause. If the swelling comes with throbbing pain, a bad taste or a fever, ask for an urgent appointment.

Sources

  1. Gum disease, NHS, accessed September 2026
  2. Dental abscess, NHS, accessed September 2026
  3. Wisdom tooth removal, NHS, accessed September 2026
  4. Dentures (false teeth), NHS, accessed September 2026
  5. Oral thrush (mouth thrush), NHS, accessed September 2026
  6. Cold sore, NHS inform (Scotland), accessed September 2026
  7. Toothache and gum swelling, healthdirect Australia, accessed September 2026
  8. Gingivitis, healthdirect Australia, accessed September 2026
  9. Dentures, healthdirect Australia, accessed September 2026
  10. Dental injury, healthdirect Australia, accessed September 2026
  11. Wisdom teeth, Better Health Channel (Victoria), accessed September 2026
  12. Pregnancy and teeth, Better Health Channel (Victoria), accessed September 2026
  13. Teeth and medication, Better Health Channel (Victoria), accessed September 2026
  14. Pregnancy and your dental health, American Dental Association (MouthHealthy), accessed September 2026
  15. Gums: swollen, MedlinePlus (US National Library of Medicine), accessed September 2026
  16. Phenytoin, MedlinePlus (US National Library of Medicine), accessed September 2026

This article is general information about oral health. It is not a diagnosis or a substitute for advice from a dentist or doctor who knows your situation. If you have pain, swelling, bleeding that does not settle, or a problem that is getting worse, see a dental professional. In an emergency, contact your local emergency service.

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