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Medicinal Use of Cannabis


Cannabis, also called marijuana, pot, weed, or hash, is a drug that comes from the cannabis sativa (hemp plant). The medicinal use of cannabis is also called medical marijuana. The whole plant or its extracts can be used to control or relieve medical or mental health conditions. The effects may start right away and last for 3 to 4 hours. Cannabis may be taken in the form of a pill, capsule, oil, or mouth spray. Cannabis can also be smoked, baked into food, or made into tea.


Call your local emergency number (911 in the US) if:

You have any of the following signs of a heart attack:

  • Squeezing, pressure, or pain in your chest
  • You may also have any of the following:
    • Discomfort or pain in your back, neck, jaw, stomach, or arm
    • Shortness of breath
    • Nausea or vomiting
    • Lightheadedness or a sudden cold sweat

Call your doctor if:

  • Your symptoms do not improve.
  • You feel you are becoming dependent on cannabis.
  • You have stopped using cannabis, and feel that you cannot cope with your withdrawal symptoms.
  • You have questions or concerns about your condition or care.

Medical conditions or symptoms cannabis can be used to treat:

  • Pain or inflammation
  • Nausea, vomiting, loss of appetite, or weight loss
  • Tingling or numbness from nerve damage
  • Mood and sleep problems
  • Muscle spasms, tremors (shaking), seizures, or tics
  • Fluid pressure in the eye from glaucoma

Risks of cannabis use:

  • Cannabis can vary in quality and strength. It may work well for some people, but not for others. The amount of cannabis needed, when to use it, or if it is working may not be clear. It may interfere with your ability to drive a car or operate machinery. If you are pregnant and use cannabis, it may prevent your unborn baby from growing normally.
  • Cannabis can make you feel tired, drunk, dizzy, or high. It can also cause or worsen some of the effects you are trying to relieve. Cannabis can cause anxiety, confusion, decreased memory, or difficulty learning. Cannabis increases the risk of panic disorder, depression, or seeing or hearing things that are not real. If you use cannabis for a long time and then stop, you may have withdrawal symptoms. You may feel angry, anxious, nervous, or restless. You may lose your appetite, lose weight, or have problems sleeping.
  • Cannabis may contain harmful substances, such as metals or fungus. It may increase your risk for a lung infection, long-term bronchitis, asthma, or other lung diseases. Smoking cannabis may increase your risk of cancer of the head, neck, and lungs. Cannabis may also increase the risk of a heart attack or stroke. When taken with other medicine, cannabis increases the risk for side effects.
  • Cannabis can cause problems absorbing nutrients if you have liver problems. Also, if you have liver problems, cannabis use can cause your liver to scar and not work properly.

What you should know about cannabis use:

  • Learn and follow the laws about the use of medicinal cannabis in the area where you live.
  • Tell your healthcare providers about all of the drugs you take. If you use cannabis, tell them when and why you use it.
  • See your healthcare provider regularly. Your provider may want to check your blood pressure or make sure cannabis is not affecting other medicines you take.
  • Talk to your healthcare provider about the use of cannabis pills, capsules, sprays, or vaporizers, instead of cigarettes.
  • Do not smoke or vape cannabis if you have respiratory problems such as asthma or COPD.
  • Do not use cannabis if you are pregnant or breastfeeding. Cannabis stays in fat cells and can be transferred slowly to your baby over a long period of time. Cannabis can affect your baby's growth and development.
  • Do not drive or use heavy machinery when you use cannabis.
  • Do not drink alcohol or use other drugs or medicines while you are using cannabis.

What you need to know about cannabidiol (CBD):

CBD is a chemical produced naturally in cannabis. CBD does not contain tetrahydrocannabinol (THC), the chemical that causes a cannabis high. CBD can be used to help with a substance abuse disorder or to relieve anxiety or depression. CBD may help relieve pain, lower inflammation, and control MS muscle spasms. CBD may also help control some types of seizures. CBD is an extract. This means it was separated from the rest of the marijuana plant. It is often made into an oil and dropped under the tongue.

Follow up with your healthcare provider as directed:

Write down your questions so you remember to ask them during your visits.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.