what causes ulcers in your mouth

Mouth ulcers (canker sores) usually happen when the lining of your mouth gets irritated or your immune system overreacts to something.

Main everyday causes

• Minor injuries: Biting your cheek or tongue, brushing too hard, sharp teeth, braces, dentures, or hard/crusty foods can all damage the lining and trigger an ulcer.

• Stress and fatigue: Emotional stress and being run‑down can weaken your immune response and make ulcers more likely.

• Nutritional deficiencies: Low vitamin B12, iron, folate, or zinc are linked with recurrent mouth ulcers.

• Hormonal changes: Some people get more ulcers around menstruation, pregnancy, or other hormonal shifts.

• Food and product irritation:
  • Trigger foods like chocolate, nuts, coffee, spicy or acidic foods, and gluten in some people.

* Toothpastes or mouthwashes with sodium lauryl sulfate can irritate the lining and contribute to ulcers in sensitive people.

Infections and medical causes

• Viral infections: Herpes simplex (cold sore virus), chickenpox, hand‑foot‑and‑mouth disease, and others can cause painful mouth sores.

• Fungal and bacterial infections: Oral thrush and some bacterial infections can produce ulcer‑like lesions.

• Immune and systemic diseases: Conditions like coeliac disease, inflammatory bowel disease, Behçet syndrome, lupus, and some blood disorders (e.g., anemia, leukemia) can show up as recurrent or unusual mouth ulcers.

• Medicines and treatments: Certain medicines (like some painkillers, chemotherapy, or immune drugs) and radiotherapy to the head/neck can damage the mouth lining and cause ulcers.

When it’s just bad luck vs. a warning sign

Many people never find a single clear cause: they just have “recurrent aphthous ulcers,” where genetics plus triggers like stress or minor trauma bring them on.

But ulcers can be a warning sign if they:

• Last longer than 2–3 weeks
• Keep coming back in the same spot
• Are very large, very numerous, or unusually painful
• Come with weight loss, fevers, diarrhea, joint pain, or swollen lumps in the neck

In those cases, it’s important to see a dentist or doctor to rule out systemic illness, infection, or (more rarely) oral cancer.

Quick forum-style takeaway

“Most mouth ulcers come from small injuries plus stress or low vitamins, but if they keep returning, don’t just live with them—get checked to make sure nothing more serious is going on.”

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.