Medical cannabis has several potential beneficial effects.[9][10] Cannabinoids can serve as appetite stimulants, antiemetics,antispasmodics, and have some analgesiceffects,[1] may be helpful treating chronic non-cancerous pain, or vomiting and nausea caused by chemotherapy. The drug may also aid in treating symptoms of AIDS patients.[6]

The U.S. Food and Drug Administration(FDA) has not approved smoked cannabis for any condition or disease as it deems evidence is lacking concerning safety and efficacy of cannabis for medical use.[11] The FDA issued a 2006 advisory against smokedmedical cannabis stating: “marijuana has a high potential for abuse, has no currently accepted medical use in treatment in the United States, and has a lack of accepted safety for use under medical supervision.”[11] The National Institute on Drug Abuse (NIDA) states, “Marijuana itself is an unlikely medication candidate for several reasons: (1) it is an unpurified plant containing numerous chemicals with unknown health effects; (2) it is typically consumed by smoking further contributing to potential adverse effects; and (3) its cognitive impairing effects may limit its utility.”[12]

The Institute of Medicine, run by the United States National Academy of Sciences, conducted a comprehensive study in 1999[dated info] assessing the potential health benefits of cannabis and its constituent cannabinoids. The study concluded that smoking cannabis is not to be recommended for the treatment of any disease condition, but that nausea, appetite loss, pain and anxiety can all be mitigated by cannabis. While the study expressed reservations about smoked cannabis due to the health risks associated with smoking, the study team concluded that until another mode of ingestion was perfected providing the same relief as smoked cannabis, there was no alternative. In addition, the study pointed out the inherent difficulty in marketing a non-patentable herb, as pharmaceutical companies will likely make smaller investments in product development if the result is not patentable. The Institute of Medicine stated that there is little future in smoked cannabis as a medically approved medication, while in the report also concluding that for certain patients, such as the terminally ill or those with debilitating symptoms, the long-term risks are not of great concern.[13][14] Citing “the dangers of cannabis and the lack of clinical research supporting its medicinal value” the American Society of Addiction Medicine in March 2011 issued a white paper recommending a halt on use of marijuana as medication in the U.S., even in states where it had been declared legal.[15][16]

Nausea and vomiting

Medical cannabis is somewhat effective inchemotherapy-induced nausea and vomiting(CINV)[6] and may be a reasonable option in those who do not improve following preferential treatment.[17] Comparative studies have found cannabinoids to be more effective than some conventional antiemetics such as prochlorperazine,promethazine, and metoclopramide in controlling CINV,[18] but these are used less frequently because of side effects including dizziness, dysphoria, and hallucinations.[7][19]Long-term cannabis use may cause nausea and vomiting, a condition known ascannabinoid hyperemesis syndrome.[20]

A 2010 Cochrane review said that cannabinoids were “probably effective” in treating chemotherapy-induced nausea in children, but with a high side effect profile (mainly drowsiness, dizziness, altered moods, and increased appetite). Less common side effects were “occular problems, orthostatic hypotension, muscle twitching, pruritis, vagueness, hallucinations, lightheadedness and dry mouth”.[21]


Evidence is lacking for both efficacy and safety of cannabis and cannabinoids in treating patients with HIV/AIDS or for anorexia associated with AIDS. As of 2013, current studies suffer from effects of bias, small sample size, and lack of long-term data.[22]


Cannabis appears to be somewhat effective for the treatment of chronic pain, including pain caused by neuropathy and possibly also that due to fibromyalgia and rheumatoid arthritis.[23][24] A 2009 review states it was unclear if the benefits were greater than the risks,[23] while a 2011 review considered it generally safe for this use.[24] In palliative care the use appears safer than that ofopioids.[25]

Neurological problems

The use of cannabis in neurological problems, including multiple sclerosis, epilepsy, and movement problems, is not very clear.[26] Studies of the efficacy of cannabis for treating multiple sclerosis have produced varying results. The combination of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) extracts give subjective relief of spasticity, though objective post-treatment assessments do not reveal significant changes.[27]Evidence also suggests that oral cannabis extract is effective for reducing patient-centered measures of spasticity.[28] A trial of cannabis is deemed to be a reasonable option if other treatments have not been effective.[6] Its use for MS is approved in ten countries.[6][29] A 2012 review found no problems with tolerance, abuse or addiction.[30]