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A good way to wind down? A gateway substance? Or so much more?

Whether you’re 420-friendly or not, the perception of cannabis as recreational drug glosses over its immense historic, cultural, and medicinal significance.

In fact, the history of medical cannabis spans millennia, with its earliest confirmed use dating to 400AD. Scholars think this goes back further to ancient China, India, and Persia, when it was used for pain relieving, soporific, and aphrodisiac qualities.

old man with weed leaf in his hand

Most countries only outlawed cannabis recently, but two hundred years of criminalization harmed research by making cannabis impossible to access and study.

Thankfully, the transition back from vilified substance to a healing plant is well underway. Scientific opinion, public perception, and laws have all shifted, and the scale of medical research has exploded in the last few years.

With our obvious excitement to make up for lost time, it’s crucial for cannabis and the research surrounding it to be transparent, high-quality, and unbiased. After all, you have a right to be informed about how cannabis could reshape healthcare.

How does it work? Could it help you? Which medical conditions can it be used for? What are the downsides?

Let’s take a good look at what science says.

How medical cannabis works

What is the effect of cannabis on the body?

Each of us has a vast network of nerves, receptors, and chemical transmitters in our body called the endocannabinoid system, or ECS, for short.

The ECS is known to regulate a whole range of vital bodily functions, from mood, learning, and memory to immune system function, pain perception, and inflammation.

Even if you don’t use cannabis, our bodies naturally produce endocannabinoids, which act as chemical signals in the ECS. They do this by activating cannabinoid receptors dotted around the brain and body. It is thought that some of the most challenging chronic pain conditions such as IBS, fibromyalgia, and migraines are related to a deficiency in endocannabinoids.

No prize for guessing where we can find more. Yes, over 100 phytocannabinoids such as THC and CBD occur naturally in the Cannabis sativa plant. Terpenes are also found in cannabis. These aromatic compounds give bud its oh-so-distinctive smell, flavor, and color. Some terpenes have antimicrobial, antifungal, and even anti-cancer properties, and may synergize with cannabinoids to enhance their medicinal properties.

Like our own endocannabinoids, THC, CBD, and others interact with cannabinoid receptors and could be the key to a better understanding of many medical conditions.

So, with that science lesson over, let’s look at where the research stands currently.

cannabis leaf with mechanical devices

The current state of research into medical cannabis

Unfortunately, solid scientific evidence for the health effects of cannabinoids is scarce at the moment, but new research is always ongoing. That’s not to say that many people around the world don’t find relief from using cannabis and cannabinoid products, but this is yet to be replicated in well-designed, unbiased clinical trials.

One of the main reasons for this is that legislation and regulations have limited medical research. Underfunding and cannabis supply issues make it difficult for researchers to get the quantity, grade, and kind of cannabis product required for high-quality studies.

The result is that patients, healthcare providers, and policymakers are left without the information to make decisions about the use of cannabis as a medicinal product.

doctor holding a speech

Another problem is that clinical research finds it hard to replicate the subtle nuances of real-world cannabis use and users. Cannabis comes in dozens of forms and there’s a wide spectrum of ways to take it. Even within smoking, there’s a variety of devices, from the humble joint to ornate dab rigs. What this means is that it can be hard to ensure standard dosing. Some researchers have even tried to design standardized smoking techniques to get around this. Another option is to use isolated cannabinoids which offer a more precise dose but could mean that we are missing out on what the full plant has to offer, including other cannabinoids, terpenes, and flavonoids.

Our best bet in looking for the benefits of medical cannabis is to look at systematic reviews and meta-analyses. These are special studies that aggregate the findings of hundreds of trials to assess for any beneficial outcomes.

Let’s look at what evidence they can show us.

Evidence for medical cannabis

Recent studies have examined the health effects of cannabinoids in dozens of different medical conditions. Of these, researchers found that only chronic non-cancer pain, nausea and vomiting, epilepsy, and multiple sclerosis had been the focus of high-quality reviews.

Chronic pain

Overall, there is moderate evidence that cannabinoids are safe and can provide relief in chronic non-cancer-related pain. Dronabinol and nabiximols were found to have good-quality evidence for this purpose. Nabilone has also been found to have an effect, however, the studies were low in quality.


Epilepsy has one of the strongest evidence bases for cannabis. The use of cannabinoids as an anticonvulsant agent was first reported in 1843. Much of the evidence is high quality and shows that CBD is linked to a decrease in seizure frequency, particularly in patients with Lennox-Gastaut syndrome and Dravet syndrome. It is also important to mention the risk that cannabinoids can aggravate seizures and affect how other epilepsy drugs work.

Multiple Sclerosis and paraplegia

Both conditions can be associated with a painful increase in muscle tone and stiffness, known as spasticity. Several reviews have reported a significant effect favoring the use of cannabinoids for spasticity, especially in MS. Even so, the quality of evidence is not strong, and the results are not consistently positive.


Early lab studies have shown that cannabinoids and other compounds may have some anti-cancer properties, but it is not yet a proven or recommended treatment for cancer. However, medical cannabis can be used to treat symptoms associated with cancer and its treatment. Nausea and vomiting from chemotherapy are common and distressing, and there is some evidence suggesting that the cannabinoids dronabinol and nabilone can provide relief. One analysis found that cannabinoids controlled symptoms in one-third to half of the patients taking them, outperforming placebo and other anti-nausea drugs.


Some evidence suggests that cannabis can treat glaucoma, which is a build-up of pressure in the eye that can damage the optic nerve. However, the effects, if any, are temporary. So, to have a meaningful effect on glaucoma, you would need to take up a dose of THC equivalent to an average edible, 6-8 times a day! In some studies, CBD and nabiximols even led to an increase in eye pressure.

Other effects on the body

Just like any other medicine, the effect of cannabis on the body isn’t always desirable. Some (but not all) studies have linked cannabis to a range of health issues, including lung and cardiovascular disease, low fertility, and psychiatric effects. It’s important to discuss your medical history with your physician or healthcare provider before using medical cannabis.

doctor with a notebook

Conditions that can be treated with medical cannabis

There are several qualifying medical conditions for cannabis, but these vary depending on where you live. The most common qualifying medical conditions in the US and Europe are:

  • Chronic pain
  • Cancer and chemotherapy-related nausea and vomiting
  • Epilepsy
  • Glaucoma
  • Low appetite due to AIDS/Cancer
  • Multiple Sclerosis
  • Post-traumatic stress disorder

Talk to your healthcare provider if you feel medical cannabis could help you.

scrabble letters spelling the word useful

So, what’s the deal?

Does this ancient medicine hold the key to better medical care?

Understandably, those with hard-to-treat and poorly understood medical conditions are hopeful for the impact that medical cannabis could have on their lives. There are promising signs that cannabis could revolutionize the treatment of conditions like epilepsy and chronic pain.

Unfortunately, while there is a lot of material out there, the standard of evidence isn’t high enough for medical cannabis to be accepted into the mainstream just yet.

With that said, it’s still early days for cannabis research, and improved evidence will be available in the future. Continue to watch this space.

This content is meant for educational purposes only. It has been compiled with research from external sources. it is not meant to substitute any medical or legal advice. Please see your local laws for the legality of cannabis use.