Desiccants are substances that absorb moisture from the air, helping to keep environments dry. They are commonly used in packaging to protect products from humidity, which can cause damage or spoilage. Common desiccants include silica gel, calcium chloride, and activated alumina. These materials work by attracting and holding water vapor, effectively reducing humidity levels. Desiccants are often found in small packets labeled "Do Not Eat" that are included with various products, such as electronics and food items, to maintain their quality and extend shelf life.