What is the treatment for aphthous ulcers (canker sores)?

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Last updated: May 2, 2025 • View editorial policy

From the Guidelines

To treat a canker sore, start with over-the-counter options like topical benzocaine or hydrogen peroxide rinses to reduce pain and promote healing, as recommended by recent guidelines 1. When managing canker sores, it's essential to consider the complexity and diversity of oral ulcerations, which can pose considerable diagnostic and therapeutic challenges 1. The exact cause of canker sores is unknown, but stress, minor injuries, certain foods, and nutritional deficiencies can trigger them.

Treatment Options

  • Apply topical benzocaine or hydrogen peroxide directly to the sore up to four times daily to reduce pain and promote healing.
  • Use salt water rinses (1/2 teaspoon salt in 8 ounces warm water) to reduce inflammation and kill bacteria.
  • For pain relief, take ibuprofen (Advil, Motrin) 200-400mg every 6-8 hours or acetaminophen (Tylenol) 500-1000mg every 6 hours as needed.
  • Avoid spicy, acidic, or rough foods that can irritate the sore further.

Persistent or Severe Sores

For persistent or severe sores, prescription options include triamcinolone dental paste (Kenalog in Orabase), prescription-strength mouthwashes containing lidocaine or steroids, or oral steroids in extreme cases 2. It's crucial to consult a healthcare provider if sores are larger than 1cm, last longer than two weeks, or occur frequently.

Quality of Life

Treatment should be tailored according to how it affects the patient's quality of life, and oral hygiene is essential in managing canker sores 2. By following these guidelines and considering the patient's individual needs, healthcare providers can improve outcomes and reduce unnecessary financial burden 1.

From the FDA Drug Label

Temporarily relieves pain associated with the following mouth and gum irritations: toothache sore gums canker sores braces minor dental procedures The treatment for canker sore is benzocaine (TOP), which temporarily relieves pain associated with canker sores 3.

  • Key points: + Relieves pain associated with canker sores + Temporary relief If symptoms do not improve in 7 days, or if irritation, pain or redness persists or worsens, swelling, rash or fever develops, stop use and ask a doctor or dentist 4.

From the Research

Treatment Options for Canker Sores

  • Chlorhexidine has been studied as a potential treatment for canker sores, with a study from 1993 comparing its efficacy to triamcinolone acetonide in treating recurrent aphthous stomatitis 5.
  • The study found that there was no significant difference in pain intensity and perception between the two treatments, suggesting that chlorhexidine may be a viable option for treating canker sores.
  • Another study from 2019 investigated the use of intralesional triamcinolone acetonide therapy for inflammatory oral ulcers, including canker sores, and found that it was an effective treatment in achieving complete resolution of symptoms in 81.7% of patients 6.

Mechanism of Action

  • Chlorhexidine is a widely used antiseptic that has been shown to have persistent antimicrobial effects due to its strong binding to proteins in the skin and mucosa 7.
  • This property makes it an effective ingredient in mouthwashes and other oral care products, and may contribute to its potential efficacy in treating canker sores.

Efficacy and Safety

  • The 1993 study found that chlorhexidine was not significantly different from triamcinolone acetonide in terms of pain control, suggesting that it may be a safe and effective alternative treatment for canker sores 5.
  • The 2019 study found that intralesional triamcinolone acetonide therapy was effective in reducing pain and ulcer size, with a significant reduction in pain score and ulcer size after the first injection 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Triamcinolone acetonide versus chlorhexidine for treatment of recurrent stomatitis.

Oral surgery, oral medicine, and oral pathology, 1993

Research

Intralesional triamcinolone acetonide therapy for inflammatory oral ulcers.

Oral surgery, oral medicine, oral pathology and oral radiology, 2019

Research

Chlorhexidine--pharmacology and clinical applications.

Anaesthesia and intensive care, 2008

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.