Most are harmless, but here’s when to get them checked.
If you’ve ever had a painful sore inside your mouth — maybe on your tongue, cheek, or inner lip — you’ve likely experienced a mouth ulcer, also known as a canker sore.
They’re surprisingly common, but because they can hurt or linger, many people wonder:
“Is this something I should worry about?”
Here’s everything you need to know about what causes mouth ulcers, how to manage them, and when to see your dentist.
🩹 What Are Mouth Ulcers?
Mouth ulcers are small, shallow sores that develop inside the mouth — not to be confused with cold sores, which appear outside the mouth and are caused by the herpes virus.
They typically appear as:
- A white or yellowish centre with a red border
- Round or oval in shape
- Found on the tongue, cheeks, lips, or soft palate
- Painful, especially when eating spicy, salty, or acidic foods
Most minor mouth ulcers heal on their own within 7–10 days.
🧪 What Causes Mouth Ulcers?
They can be triggered by a variety of factors, including:
- Minor trauma (e.g., biting your cheek, sharp food, or dental appliances)
- Stress or lack of sleep
- Nutritional deficiencies (especially B12, iron, or folate)
- Hormonal changes
- Food sensitivities (to citrus, chocolate, nuts, or spicy foods)
- Certain medications or underlying health conditions
- Viral or autoimmune conditions (less common)
If you get ulcers often, your dentist may explore what’s triggering them and recommend prevention strategies.
🛠 How to Treat a Mouth Ulcer at Home
Most mouth ulcers heal naturally without treatment. But to reduce discomfort and speed up healing, you can:
- Rinse with warm salt water (½ tsp salt in a cup of water)
- Use over-the-counter gels or rinses for pain relief (e.g., Orajel, benzocaine)
- Avoid spicy, acidic, or rough-textured foods
- Use a soft-bristled toothbrush and brush gently
- Stay hydrated and get plenty of rest
🚩 When to See a Dentist or Doctor
While most mouth ulcers are harmless, you should book an appointment if:
- The ulcer lasts longer than 2 weeks
- It’s extremely painful or getting worse
- You have multiple or frequent ulcers
- You notice swollen lymph nodes, fever, or fatigue
- You have ulcers alongside other symptoms, like weight loss or rash
- The sore looks unusual, bleeds easily, or is not healing over time
In rare cases, a persistent sore could indicate a more serious condition — including oral cancer — so it’s always better to get it checked for peace of mind.
Final Thoughts
Mouth ulcers are common, usually harmless, and often triggered by simple things like stress, minor injury, or diet. While they can be painful, they typically go away on their own — but if they’re frequent, slow to heal, or causing concern, your dental team is here to help.
Have a sore that won’t go away? Book an appointment today — we’ll take a closer look and make sure your mouth is healing the way it should.