Alum is a chemical compound that typically appears as a white crystalline substance. It is commonly used in various applications, including water purification, food processing, and as a mordant in dyeing fabrics. The most well-known type of alum is potassium aluminum sulfate, which has the formula KAl(SO₄)₂·12H₂O. In addition to its industrial uses, alum has a long history in traditional medicine and is sometimes used in home remedies for its astringent properties. It can help stop bleeding and reduce inflammation. However, it is important to use alum carefully, as excessive consumption can lead to health issues.