There is no difference between “medical marijuana” and marijuana bought on the street. The difference is “how” the marijuana is used—that is, it is being used for the treatment of a medical condition.
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 marijuana’s use for certain medical conditions. Marijuana is not legal or considered medicine by the Federal Government. However, some of the active chemicals in marijuana, called cannabinoids, have been approved by the U.S. Food and Drug Administration (FDA) for two medications. These pill versions of THC have been approved to treat nausea (feeling sick) in cancer patients and to increase appetite in some patients with AIDS. Also, a new product—a mixture of THC and cannabidiol (another chemical found in the marijuana plant)—is available in several countries outside the United States as a mouth spray. There is some evidence cannabidiol may be useful in treating seizures in children with severe epilepsy, so a cannabidiol-based drug also is now being studied.
It is important to remember that because marijuana is usually smoked into the lungs and has ingredients that can vary from plant to plant, its health risks may outweigh its value as a treatment, especially for people that are not very sick with cancer or other life-threatening diseases. Scientists continue to study safe ways that THC and other marijuana ingredients can be used as medicine.
For more information, see Drug Facts—Is Marijuana Medicine?