A canker sore, also known as an aphthous ulcer, is a common, small, and painful lesion that forms on the soft tissues inside the mouth, such as the tongue, cheeks, or gums. Unlike cold sores, these ulcers are not contagious and are not caused by the herpes virus. Sodium bicarbonate, commonly known as baking soda, is a readily available household item used as a simple home remedy for temporary relief from the discomfort of these sores. This article explains the specific mechanism by which baking soda provides this soothing effect.
What Causes the Pain of Canker Sores
The pain associated with a canker sore results from the breakdown of the oral mucosal barrier. This ulceration exposes the underlying, sensitive tissues and nerve endings to the environment of the mouth. The mouth’s environment is frequently acidic due to foods, beverages, and the metabolic byproducts of oral bacteria. When these acidic elements contact the open wound, they cause acute irritation and inflammation, generating a stinging or burning sensation. Constant friction from movement, like talking or chewing, also aggravates the exposed tissue.
The Alkalinity of Baking Soda and Its Effects
Baking soda, or sodium bicarbonate (NaHCO₃), acts as a mild base, meaning it is highly alkaline. When dissolved in water, this solution has the ability to neutralize acids. Introducing this alkaline solution into the mouth directly counteracts the localized acidic environment surrounding the canker sore. This chemical reaction raises the pH balance in the area, reducing the concentration of irritants that cause pain.
The neutralization process immediately calms the exposed nerve endings that were being aggravated by the acidity. This action helps reduce localized inflammation and provides a noticeable sensation of relief. Furthermore, sodium bicarbonate possesses mild desiccant, or drying, properties. By drawing fluid from the ulcerated tissue, baking soda can slightly shrink the sore’s size. This combined effect of pH neutralization and mild tissue drying creates a more hospitable environment for natural healing.
Preparation and Usage Guidelines
Baking soda can be applied to a canker sore using two primary methods: a mouth rinse or a spot-applied paste.
Mouth Rinse
For a mouth rinse, dissolve one teaspoon of sodium bicarbonate into about a half-cup of warm water. Swish this mixture thoroughly around the mouth for 15 to 30 seconds, ensuring the solution contacts the sore, and then spit it out. This method is effective for treating multiple sores or those in hard-to-reach areas.
Spot-Applied Paste
Alternatively, create a paste for direct application. Mix a small amount of baking soda with just enough water to form a thick, cohesive paste. Gently dab this paste directly onto the canker sore using a clean cotton swab or your fingertip. Allow the paste to remain on the sore for several minutes before gently rinsing your mouth with plain water.
Both the rinse and the paste can be repeated every few hours as needed throughout the day for continued comfort. While ingesting small amounts of the solution is not generally harmful, avoid swallowing large quantities. Always rinse your mouth after using the paste to remove the residual powder. If the canker sore persists beyond two weeks or is accompanied by a fever, consult a healthcare professional.