Home > Health Library > Marijuana
Marijuana is a drug that is made up of the leaves, flowers, and buds of the hemp plant Cannabis sativa. It is often smoked in pipes or hand-rolled cigarettes. But it can also be vaporized, applied to the skin, cooked in food, or brewed into tea.
In the United States, several states have made some forms of marijuana legal, mainly as a medical treatment. It may be used for symptoms like pain, nausea, and lack of appetite. But possession of marijuana is still a crime under federal law.
People often use marijuana for the way it makes them feel. Using it may make them:
But it may also cause unwanted side effects, such as:
The immediate effects of marijuana depend on the potency of its main active chemical, THC. THC affects areas of the brain that are involved in important functions such as memory, concentration, and coordination.
How quickly the effects start depends on several things, including how it was taken. When marijuana is smoked, the effects can usually be felt within seconds after inhaling. The effects last about 2 to 3 hours.
Marijuana is absorbed by fatty tissues in
various organs of the body. THC usually can be detected in urine
several days after marijuana has been smoked. If marijuana use is heavy,
THC may be found in urine for weeks after use has stopped.
Long-term regular use of marijuana may cause problems such as:
Some people who regularly use marijuana become addicted. This means that they keep using marijuana even though it's having harmful effects on their lives.
The risk of addiction is higher in people who:
People who use marijuana often and then quit may have withdrawal symptoms. These include anxiety, trouble sleeping, and intense cravings for the drug.
Synthetic marijuana is made of dried plant material that is treated with chemicals that produce effects like marijuana's effects. It is sold in the form of incense under many names, such as K2 or Spice. The labels often claim that these products are "safe" or "natural." But in fact, the active chemicals are created in a lab. And they have not been tested for safety.
But young people often try these products because they are easy to buy and they may not be detected by drug tests.
People think that using these drugs will make them feel the same as when they use marijuana. But these drugs are stronger than marijuana. And the effects are hard to predict. That's because the type and strength of the chemicals used are often unknown. Some people have reported severe symptoms, such as:
Other Works Consulted
American Lung Association (2012). Health hazards of smoking marijuana. Available online: http://www.lung.org/stop-smoking/about-smoking/health-effects/marijuana-smoke.html.
National Cancer Institute (2013). Cannabis and Cannabinoids PDQ – Health Professional Version. Available online: http://www.cancer.gov/cancertopics/pdq/cam/cannabis/healthprofessional.
National Institute on Drug Abuse (2012). DrugFacts: Marijuana. Available online: http://www.drugabuse.gov/publications/drugfacts/marijuana.
National Institute on Drug Abuse (2012). DrugFacts: Spice (Synthetic Marijuana). http://www.drugabuse.gov/publications/drugfacts/spice-synthetic-marijuana.
Accessed September 30, 2013.
ByHealthwise StaffPrimary Medical ReviewerPatrice Burgess, MD - Family MedicineSpecialist Medical ReviewerPeter Monti, PhD - Alcohol and Addiction
Current as ofFebruary 24, 2016
Current as of:
February 24, 2016
Patrice Burgess, MD - Family Medicine & Peter Monti, PhD - Alcohol and Addiction
To learn more about Healthwise, visit Healthwise.org.
© 1995-2016 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
I Want To...
Join Our Social Network