A desiccant is a substance that absorbs moisture from the air, helping to keep environments dry. Commonly used in packaging, desiccants prevent damage to products like electronics, food, and pharmaceuticals by reducing humidity levels. Silica gel is one of the most well-known desiccants, often found in small packets labeled "Do Not Eat." Other types include clay and molecular sieves, each with specific applications. Desiccants are essential in various industries to maintain product quality and extend shelf life.