Marijuana is a green, brown, or gray mixture of dried, shredded leaves, stems, seeds, and flowers of the hemp plant (Cannabis sativa). Cannabis is a term that refers to marijuana and other drugs made from the same plant. Other forms of cannabis include sinsemilla, hashish, and hash oil. All forms of cannabis are mind-altering (psychoactive) drugs.

The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). Short-term effects of marijuana use include problems with memory and learning, distorted perception, difficulty in thinking and problem solving, loss of coordination, increased heart rate, and anxiety.

Marijuana is being studied in the treatment of nausea and vomiting caused by chemotherapy or opiate drugs, such as morphine sulfate. Marijuana is also being studied in the treatment of pain.