It always winds up in some kind of flaming war.
Drug prohibition is a ridiculous criminal joke that is destroying America.
The arguments are mainly against "smoked" marijuana for medical purposes.
To reduce the intraocular pressure caused by glaucoma, it would require smoking 10 joints/day, every day. But any form of marijuana for glaucoma, however, is contraindicated due to its negative effect on the optic nerve.
No major medical association supports smoked marijuana for medical reasons. None.
One other little ditty for you. 99% of medical marijuana patients (in a California survey) were already smoking marijuana for their "condition" prior to seeing a doctor. Their doctors were not recommending marijuana -- they were simply authorizing it.
The "condition" in 2 out of 3 cases? Pain.