A vaporizer or vapouriser is a device used to extract for inhalation the active ingredients of plant material, commonly cannabis, tobacco or other herbs or blends (phyto-inhalation). Vaporization is an alternative to burning (smoking) which avoids the production of irritating, toxic, and carcinogenic by-products by heating the material so its active compounds boil off into a vapor. No combustion occurs, so no smoke or taste of smoke is present. Vapor ideally contains virtually zero particulate matter or tar, and significantly lower concentrations of noxious gases such as carbon monoxide. Vaporizers contain various forms of extraction chambers including straight bore, venturi or sequential venturi and are made of materials such as metal or glass. The extracted vapor may be collected in a jar or inflatable bag, or inhaled directly through a hose or pipe. With little to no smoke produced and cooler temperatures, less material is required to achieve a given level of effect. Hence, the irritating and harmful effects of smoking are greatly reduced or eliminated as is secondhand smoke. In comparison to other drug delivery methods such as ingestion, vaporization has a more rapid onset of pharmacological effect, direct delivery into the bloodstream (via the lungs), and more precise titration such that the desired level is reached and not exceeded, enabling consistent and appropriate dosage.