Medical cannabis has a long history as a natural analgesic,1 and is now legal in 30 U.S. states,2,3 the majority of which allow limited use of medical marijuana under certain medical circumstances. The medicinal qualities of marijuana are primarily due to high amounts (about 10 to 20 percent) of cannabidiol (CBD), medicinal terpenes and flavonoids.

Tetrahydrocannabinol (THC) is the psychoactive component of marijuana that makes you feel “stoned,” but it too has valuable medical benefits, so depending on your problem, you may want higher or lower levels of THC. Cannabinoids interact with your body by way of naturally occurring cannabinoid receptors embedded in cell membranes throughout your body.

There are cannabinoid receptors in your brain, lungs, liver, kidneys, immune system and more. Both the therapeutic and psychoactive properties of marijuana occur when a cannabinoid activates these cannabinoid receptors.

Cannabis Has Long History of Use for Pain, Seizures and More

The U.S. government, through the Department of Health and Human Services (HHS), actually holds a patent on CBD as an antioxidant and neuroprotectant — an ironic and paradoxical situation considering the U.S. Drug Enforcement Administration has classified cannabis as a Schedule 1 controlled substance, which by definition has no accepted medical use.

This federal classification also makes it very difficult, time consuming and expensive to study the health effects of marijuana. Labs have to jump through a lot of legal hoops before being granted permission to study Schedule 1 drugs. Despite such difficulties, a number of studies have found a wide range of uses for the herb. For example, The Journal of Pain,4 a publication by the American Pain Society, has a long list of studies on the pain-relieving effects of cannabis.

Cannabis also has been used for over 80 years for drug-resistant seizure disorders. In January 2015, the American Academy of Pediatrics updated its policy statement on marijuana,5 acknowledging that cannabinoids “may currently be an option for … children with life-limiting or severely debilitating conditions and for whom current therapies are inadequate.”

According to the National Institute on Drug Abuse,6 which also has information relating to the medicinal aspects of marijuana, preclinical and clinical trials are also underway to test marijuana and various extracts for the treatment of a number of diseases, including autoimmune diseases such as multiple sclerosis and Alzheimer’s disease, inflammation, substance use disorders and mental disorders.

CBD oil has also been shown7 to protect the brain of stroke patients and those with Parkinson’s. It may also slow neurodegeneration caused by alcohol abuse.

Cannabis Shows Promise as Anticancer Agent

Doctors working with medical cannabis are also using it to treat cancer-related side effects, and evidence suggests the herb may even have antitumor effects all on its own, with dozens of studies pointing to marijuana’s effectiveness against many different types of cancer, including brain cancer, breast, prostate, lung, thyroid, colon and pituitary cancer, melanoma and leukemia.

It fights cancer via at least two mechanisms that make it difficult for a cancer to grow and spread: It’s proapoptotic (meaning it triggers apoptosis or cellular suicide of cancer cells while leaving healthy cells untouched) and antiangiogenic (meaning it cuts off a tumor’s blood supply). As recently reported by Scientific American:8

“… while the available data are limited, research that has been conducted around antitumor effects of cannabinoids so far shows great promise. The International Journal of Oncology published a study9 last year, for example, indicating that cannabinoids successfully kill cancer cells, and the benefits increase when combined with chemotherapy.

An early preclinical study10 we recently conducted also found that cancer cells derived from patient blood samples were differentially sensitive to the two main active compounds in cannabis — tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA).

A number of other laboratory and animal studies have been conducted in recent years on colon, breast and brain cancers.11They indicate that cannabinoids may inhibit tumor growth by blocking cell growth, causing cell death and blocking the development of blood vessels that tumors require to grow.”