"We found that 25 mg herbal cannabis with 9.4% tetrahydrocannabinol, administered as a single smoked inhalation three times daily for five days, significantly reduced average pain intensity compared with a 0% tetrahydrocannabinol cannabis placebo in adult participants with chronic post-traumatic or postsurgical neuropathic pain. We found significant improvements in measures of sleep quality and anxiety. We have shown the feasibility of a single-dose delivery method for smoked cannabis, and that blinding participants to treatment allocation is possible using this method."


Ware, Mark A.; Wang, Tongtong; Shapiro, Stan; Robinson, Ann; Ducruet, Thierry; Huynh,Thao; Gamsa, Ann; Bennett, Gary J.; and Collet, Jean-Paul,"Smoked cannabis for chronic neuropathic pain: a randomized controlled trial" (Ottawa, ON: Canadian Medical Association, October 5, 2010), p. E697-E700.