No. potpourri does NOT contain THC.
Marijuana
No. Only Marijuana, Marinol, Cesamet, and Sativex contain THC at this time.
THC is found in Marijuana its what gets you high when you smoke weed.
Yes, I don't smoke but I get high off the hot box my friends do in their car, if you inhale exhaled smoke, there is still THC that will enter Your system
Medical marijuana
NO! Lyrica does not contain THC
Obviously But watch out for a headache
Yes, the more you smoke, the more THC is absorbed into your body
Cesamet contains a synthetic form of THC, the active ingredient of marijuana.
Yes, as long as you had it in your mouth.
There is no point in smoking the roots of the marijuana plant, as there are no trichromes in the roots. Trichromes contain THC, which you can see in the buds and cola. To answer your question - "You don't."