There is no difference between marijuana dispensed to treat a medical condition and marijuana bought on the street for recreational use. The difference is just in how it is used.
The marijuana plant contains chemicals that may be useful for treating a range of illnesses or symptoms. A growing number of states (23 as of August 2014) have legalized the plant’s use for certain medical conditions. Although it is not legal or considered medicine by the Federal Government a few medications made from active chemicals in the plant called cannabinoids have been approved by the U.S. Food and Drug Administration (FDA). One of these cannabinoids, THC, has some medicinal properties in addition to its mind-altering effects. Pill versions of THC have been approved to treat nausea (feeling sick) in cancer patients and to increase appetite in some patients with AIDS.
Another cannabinoid chemical called cannabidiol, which doesn’t have mind-altering effects, is also being studied for its possible uses as medicine. A new medication with a combination of THC and cannabidiol is available in several countries outside the United States as a mouth spray for treating symptoms of multiple sclerosis. There is some early evidence that cannabidiol may be useful in treating seizures in children with severe epilepsy, so a cannabidiol-based drug for that is also now being studied.
It is important to remember that because marijuana is often smoked, it can hurt lung health; these health risks as well as the way it impairs mental functioning may outweigh its value as a medical treatment, especially for people that are not very sick with cancer or other life-threatening diseases. Another problem with smoking or eating marijuana plant material is the ingredients vary a lot from plant to plant, so there is no way to get a precise dose every time or even know what dose you are getting. This is why scientists are busy studying safe ways that THC, cannabidiol, and other chemicals can be extracted from the marijuana plant to create safe medicines.
For more information, see Drug Facts—Is Marijuana Medicine?