A vaporizer (or vapouriser) is a device used to sublimate the active ingredients of plant material, commonly cannabis, tobacco, or any of many other therapeutic or medicinal herbs or blends (phyto-inhalation; see also: aromatherapy). Vaporization is an alternative to smoking. Rather than burning the herb, which produces irritating, toxic, and carcinogenic by-products, a vaporizer heats the material in a partial vacuum so that the active compounds contained in the plant boil off into a vapor.