The terms active packaging, intelligent packaging, and smart packaging refer to packaging systems used with foods, pharmaceuticals, and several other types of products. They help extend shelf life, monitor freshness, display information on quality, improve safety, and improve convenience. The terms active packaging, intelligent packaging, and smart packaging refer to packaging systems used with foods, pharmaceuticals, and several other types of products. They help extend shelf life, monitor freshness, display information on quality, improve safety, and improve convenience. The terms are closely related. Active packaging usually means having active functions beyond the inert passive containment and protection of the product. Intelligent and smart packaging usually involve the ability to sense or measure an attribute of the product, the inner atmosphere of the package, or the shipping environment. This information can be communicated to users or can trigger active packaging functions. Programmable matter, smart materials, etc can be employed in packages. Depending on the working definitions, some traditional types of packaging might be considered as 'active' or 'intelligent'. More often, the terms are used with new technologically advanced systems: microelectronics, computer applications, nanotechnology, etc. For many years, desiccants have been used to control the water vapor in a closed package. A desiccant is a hygroscopic substance usually in a porous pouch or sachet which is placed inside a sealed package. They have been used to reduce corrosion of machinery and electronics and to extend the shelf life of moisture sensitive foods and drugs. Corrosion inhibitors can be applied to items to help prevent rust and corrosion. Volatile corrosion inhibitors (VCI) or vapor phase corrosion inhibitors can be provided inside a package in a pouch or can be incorporated in a saturated overwrap of special paper. Many of these are organic salts that condense on the metal to resist corrosion. Some films also have VCI emitting capability.