Can you use alum to gargle with?

Alum can be used as a gargle to treat canker sores and other minor mouth irritations due to its astringent properties that cause proteins to congeal and shrink. When using alum as a gargle, it is important to dissolve it in warm water.

The recommended dosage for gargling with alum is ¼ teaspoon mixed in 8 ounces of warm water. Gargling with alum water should be done several times a day, as needed. It is important not to swallow the alum water, as it can cause stomach upset. If you experience any unpleasant side effects from using alum as a gargle, discontinue use and talk to your doctor.