there's probably a study somewhere but rule of thumb - if you're lighting it, smoking it, and inhaling it you can be pretty sure it's not good for you and has some relationship to oral cancer. That's one of the reasons that medical marajuana comes in pill form.
Regards JoAnne

JoAnne - Caregiver to husband, cancer rt. tonsil, mets to soft palate, BOT, 7 lymph nodes - T3N2BM0, stage 4. Robotic assisted surgery, radical neck dissection 2/06; 30 IMTX treatments and 4 cycles of cisplatin completed June 06.