After you take a drag off a joint or a pull off a bong, inhaled smoke travels from your mouth into your lungs. The inside of your lungs are lined with millions of air sacs called alveoli, and combined, they have a huge surface area. Compounds in cannabis smoke, such as THC & CBD, enter your bloodstream via the air sacs in your lungs, traveling first to your brain, and then the rest of your body. This happens within seconds, and the cannabis consumer will likely feel the effects of smoking within minutes.