Survey data and several recent FDA-designed chemical trials have indicated that inhaled marijuana could significantly alleviate neuropathic pain. A pair of randomized, placebo-controlled clinical trials had demonstrated that neuropathy in patients with HIV could be reduced with cannabis by more than 30 percent compared to placebo.
A 2007 University of California at San Diego double-blind, placebo-controlled trial reported that inhaled cannabis has the potential of significantly reducing capsaicin-induced pain in healthy volunteers. Both high and low doses of inhaled cannabis reduced neuropathic pain of diverse causes in subjects unresponsive to standard pain therapies, according to a 2008 University of California at Davis double-blind, randomized clinical trial. A 2010 McGill University study has revealed that smoked cannabis significantly improved measures of pain, sleep quality and anxiety in participants with refractory pain for which conventional therapies had failed.
In 2008, investigators at the University of Milan concluded: “[T]he use of a standardized extract of Cannabis sativa … evoked a total relief of thermal hyperalgesia, in an experimental model of neuropathic pain, … ameliorating the effect of single cannabinoids,” investigators concluded. … “Collectively, these findings strongly support the idea that the combination of cannabinoid and non-cannabinoid compounds, as present in [plant-derived] extracts, provide significant advantages in the relief of neuropathic pain compared with pure cannabinoids alone.”
 New York Times. October 21, 1994. “Study says 1 in 5 Americans suffers from chronic pain.”
 Cone et al. 2008. Urine drug testing of chronic pain patients: licit and illicit drug patterns. Journal of Analytical Toxicology 32: 532-543.
 Abrams et al. 2007. Cannabis in painful HIV-associated sensory neuropathy: a randomized placebo-controlled trial. Neurology 68: 515-521.
 Ellis et al. 2008. Smoked medicinal cannabis for neuropathic pain in HIV: a randomized, crossover clinical trial. Neuropsychopharmacology 34: 672-80.
 Wallace et al. 2007. Dose-dependent effects of smoked cannabis on Capsaicin-induced pain and hyperalgesia in healthy volunteers Anesthesiology 107: 785-796.
 Wilsey et al. 2008. A randomized, placebo-controlled, crossover trial of cannabis cigarettes in neuropathic pain. Journal of Pain 9: 506-521.
 Ware et al. 2010. Smoked cannabis for chronic neuropathic pain: a randomized controlled trial. CMAJ 182: 694-701.
 Comelli et al. 2008. Antihyperalgesic effect of a Cannabis sativa extract in a rat model of neuropathic pain. Phytotherapy Research 22: 1017-1024.
 Johnson et al. 2009. Multicenter, double-blind, randomized, placebo-controlled, parallel-group study of the efficacy, safety and tolerability of THC: CBD extract in patients with intractable cancer-related pain. Journal of Symptom Management 39: 167-179.
 University of San Diego Health Sciences, Center for Medicinal Cannabis Research. February 11, 2010. Report to the Legislature and Governor of the State of California presenting findings pursuant to SB847 which created the CMCR and provided state funding.