Canker sores (aphthous ulcers) are common, painful, non-contagious lesions that develop on the soft tissues inside the mouth, such as the tongue, cheeks, or gums. These shallow ulcers typically appear white or yellow with a red border and can make speaking and eating uncomfortable. People often use potassium aluminum sulfate, known as alum, as a traditional home remedy to accelerate healing and provide quick pain relief. Alum is readily available as a powder and helps dry out and shrink the ulcerated tissue.
Step-by-Step Application and Timing
The preparation for using alum involves creating a small amount of paste to ensure the powder remains in contact with the lesion. Mix a tiny pinch of alum powder with a drop of water until it forms a thick consistency. Before application, gently blot the canker sore with a clean tissue to remove excess moisture, allowing the alum to adhere better.
The precise duration for the application of alum is generally one minute. Using a clean fingertip or cotton swab, press a small amount of the paste directly onto the canker sore, ensuring it covers the entire lesion. This short, focused contact time is sufficient to achieve the desired effect.
Leaving the alum on longer is unnecessary and may increase the stinging or burning sensation. After the minute has passed, rinse the mouth thoroughly with water to remove all traces of the powder. Avoid swallowing the alum, as ingesting large amounts can be hazardous.
How Alum Works to Treat Canker Sores
Alum functions as a powerful astringent, which is the primary reason for its effectiveness against canker sores. Its chemical structure causes it to draw fluid from the ulcerated tissue. This dehydration process shrinks the surrounding tissues, helping to dry out the lesion.
The astringent action also works by precipitating proteins on the cell surfaces of the ulcer. This coagulation forms a thin, protective layer or crust over the open wound. This physical barrier immediately reduces exposed nerve endings, which lessens pain and tenderness.
By shrinking the lesion and forming a protective seal, alum helps expedite the natural recovery process. Studies suggest alum can decrease the size of the ulcer and the severity of pain, leading to a faster recovery period.
When to Seek Professional Advice
While alum offers a quick remedy for minor discomfort, it is important to recognize the limits of home treatment. Consult a doctor or dentist if a canker sore persists for longer than two weeks, as most minor sores heal on their own within this timeframe. Sores that are unusually large, appear in clusters, or are frequently recurrent may indicate a need for professional evaluation.
Seek medical attention if the pain makes eating, drinking, or swallowing difficult, or if the sore is accompanied by a fever. These symptoms could suggest a more serious underlying issue or a secondary infection requiring prescription treatment. Alum is not recommended for young children who cannot reliably spit out the rinse water, due to the risk of accidental ingestion.