---
title: "Mouth ulcers: Symptoms, Causes & Treatment | HealthAnswers"
description: "A plain-English guide to mouth ulcers — causes, how to ease them, and when to get one checked."
url: https://healthanswers.co.uk/conditions/mouth-ulcers/
robots: noindex
---

# Mouth ulcers: Symptoms, Causes & Treatment | HealthAnswers

Health A–Z

A plain-English guide to mouth ulcers — causes, how to ease them, and when to get one checked.

Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 3 July 2026

## Quick answer

What are mouth ulcers? Mouth ulcers are small, painful sores inside the mouth. They are very common, usually harmless, and most heal by themselves within a week or two. Pharmacy treatments can ease the pain — but any ulcer lasting more than 3 weeks should be checked.

## Who is this page for?

This page is for people in the UK who want a plain-English overview of Mouth ulcers, including when to seek help and what NHS care usually involves. It explains general information, not what is wrong with you personally.

## Who should skip this page?

Skip this page if you need a diagnosis, a prescription, or emergency care. It cannot replace a GP, pharmacist, NHS 111 or 999. If you are in immediate danger, call 999; for urgent advice that is not life-threatening, call 111 in England, Scotland or Wales, or use your GP out-of-hours service in Northern Ireland.

On this page 4 sections

## Key facts about mouth ulcers

- Mouth ulcers are common, painful sores inside the mouth.
- Most heal on their own within 1 to 2 weeks.
- Pharmacy gels and rinses can ease the pain.
- An ulcer lasting more than 3 weeks should always be checked.

## What are mouth ulcers?

Mouth ulcers are small, shallow sores that appear inside the mouth — on the cheeks, lips, tongue or gums. They can sting, especially when eating or drinking, but they are very common and usually harmless, healing on their own within a week or two.

## What causes them

Most ulcers are caused by minor damage or everyday factors:

- biting the inside of the cheek, or rubbing from sharp teeth or braces

- stress and tiredness

- certain foods (often acidic or spicy)

- hormonal changes, or stopping smoking

Recurring ulcers can sometimes be linked to vitamin deficiencies or underlying conditions, which is worth exploring with a GP if they keep coming back.

## Easing the pain

While an ulcer heals: use a pharmacy gel, spray or medicated mouthwash; avoid spicy, salty, acidic or rough-textured food; use a soft toothbrush; and stick to cool drinks. A pharmacist can recommend the best option.

## The 3-week rule

Most mouth ulcers are nothing to worry about — but **any ulcer that lasts more than three weeks should be checked by a dentist or GP**. The same goes for an ulcer that grows, bleeds, keeps returning, or is unusually painless. Persistent ulcers are usually still harmless, but they need examining to rule out serious causes, including mouth cancer, where early checking makes a real difference.

## ! When to see a GP about mouth ulcers

See a pharmacist for pain-relieving treatments. See a GP or dentist if an ulcer lasts longer than **3 weeks**, keeps coming back, grows, bleeds, or is not painful — a persistent mouth ulcer should always be examined to rule out anything serious. Also seek advice if ulcers come with other symptoms such as weight loss or feeling generally unwell.

## Common questions about mouth ulcers

What causes mouth ulcers? Common triggers include accidentally biting the cheek, sharp teeth or braces, stress, tiredness, certain foods, stopping smoking, and hormonal changes. Sometimes they relate to vitamin deficiencies or other conditions, especially if they keep recurring. How do I get rid of a mouth ulcer fast? Most heal on their own, but you can ease them with pharmacy gels, sprays or mouthwashes, avoiding spicy, acidic or rough foods, using a soft toothbrush, and drinking cool drinks through a straw if it helps. Are mouth ulcers contagious? Ordinary mouth ulcers are not contagious — unlike cold sores, which are caused by a virus and appear on or around the lips rather than inside the mouth. When should I worry about a mouth ulcer? The key rule is that any mouth ulcer lasting more than 3 weeks should be checked by a dentist or GP. Most turn out to be harmless, but persistent ulcers need examining to rule out serious causes, including mouth cancer.

## Sources

- [NHS — Mouth ulcers](https://www.nhs.uk/conditions/mouth-ulcers/)