Cannabis smoking is the inhalation of smoke or vapors released by heating the flowers, leaves, or extracts of cannabis and releasing the main psychoactive chemical, Δ9-tetrahydrocannabinol (THC), which is absorbed into the bloodstream via the lungs.
Apart from being smoked and vaporized, cannabis (and its active cannabinoids) may be ingested, placed under the tongue or applied to the skin. The bioavailability characteristics and effects of smoking and vaporizing cannabis differ from other consumption methods in having a more rapid and predictable onset of effect.