Marijuana has been used to treat pain as far back as 2900 B.C. (2).
More recently, scientists have discovered that certain components of marijuana, including CBD, are responsible for its pain-relieving effects.
The human body contains a specialized system called the endocannabinoid system (ECS), which is involved in regulating a variety of functions including sleep, appetite, pain and immune system response (3).
The body produces endocannabinoids, which are neurotransmitters that bind to cannabinoid receptors in your nervous system.
Studies have shown that CBD may help reduce chronic pain by impacting endocannabinoid receptor activity, reducing inflammation and interacting with neurotransmitters (4).
For example, one study in rats found that CBD injections reduced pain response to surgical incision, while another rat study found that oral CBD treatment significantly reduced sciatic nerve pain and inflammation (5, 6).
Several human studies have found that a combination of CBD and THC is effective in treating pain related to multiple sclerosis and arthritis.
An oral spray called Sativex, which is a combination of THC and CBD, is approved in several countries to treat pain related to multiple sclerosis.
In a study of 47 people with multiple sclerosis, those treated with Sativex for one month experienced a significant improvement in pain, walking and muscle spasms, compared to the placebo group (7).
Another study found that Sativex significantly improved pain during movement, pain at rest and sleep quality in 58 people with rheumatoid arthritis (8).