From earliest days, cannabis has been recognised for its medical uses, as well as recreational uses. References to medical uses for cannabis can be found in many ancient civilisations,  and prior to its criminlisation in 1937, cannabis “was one of the top three most prescribed medicines in the US” . Activists have campaigned for years for the decriminalisation of medical cannabis by outlining its uses in treating nausea and appetite loss in cancer patients, as pain control for patients with chronic injury, and to prevent epileptic seizures. Regardless of the debates around decriminalising recreational cannabis, we should not ignore the potential medical benefits.
Like other prohibited substances, there is no glaring difference between the cannabis purchased on the street corner, and the medical cannabis dispensed for health issues. In Colorado, where it is legal to purchase cannabis for both medical and recreational reasons, experts question why anyone would go to the trouble (and stigma ) of acquiring a prescription for medical cannabis, when they can buy recreational cannabis from the store down the road. 
The key difference between medical, and ‘street’ cannabis (where there are no legal outlets for recreational cannabis) lies in the quality and purity of the drug. Cannabis purchased on the street may be mixed with other dried herbs to lower the cost for the supplier. Or as with other recreational substances, a variety drugs such a methamphetamines may be ‘cut’ into the cannabis to create a stronger high.  A person suffering chronic pain who turns to recreational cannabis may inadvertently ingest harmful and drugs whilst attempting to control their illness. Whilst self-medicating is a risky behaviour, it can be one many people turn to when they feel there are no other options left. When trying to control symptoms with cannabis, the danger of self-medicating can be compounded by the inability to obtain a safe, pure drug.
There is a minor chemical difference between cannabis grown for medicinal purposes, and that grown for recreational purposes. Whilst both contain tetrahydrocannabinol (THC), the chemical responsible for the ‘high’, the amount varies between strains. Cannabis plants grown for recreational purposes are specially cultivated to ensure a high concentration of THC, while plants grown for medicinal purposes focus on another chemical, cannabidiol (CBD).  While conditions such as insomnia, muscle spasms and tremors, and arthritis are best treated with THC, others respond better to CBD. .
While CBD has similar effects to THC, it is unable to create the high caused by THC. CBD interacts with different receptors in the brain, causing many medically beneficial changes in our brain chemistry, without the same psychoactive properties as THC . Due to it’s inability to get people ‘high’, studies have shown CBD can be effective in controlling epilepsy, anxiety, and psychosis . While there are no strong, peer-reviewed studies showing cannabis is safe for children, many parents have found CBD rich cannabis to be effective where other conventional drugs have failed.  
Whilst recreational cannabis is usually smoked, there are a variety of methods that can be used to ingest medical cannabis. Smoking is an option for medical users, however while many studies show cannabis is safer to smoke than tobacco, there is no proof that it is risk free.  Other options include vaporising, cooking cannabis oil into foods, topical creams, and cannabis based tinctures . Especially when children are taking medical cannabis, smoking is not a likely choice, but a teaspoon of cannabis oil or capsule  are simple alternatives.
While the stereotype of a medical cannabis user differs from that of a recreational cannabis user, the drug in question is strikingly similar. Different strains of cannabis may treat different conditions and create different ‘highs’, however the over-the-counter product is, for the most case, the same substance in different packaging. However, when bought over the counter, regulated by the government (and yes, taxed) the user can be confident that they are taking a pure, controlled substance, without worrying about what may, or may not, be in the packet.