Medicinal Use of Cannabis

Medically reviewed by Drugs.com. Last updated on Aug 4, 2025.

What is the medicinal use of cannabis?

Cannabis, also called marijuana, pot, weed, or hash, is a drug that comes from the cannabis sativa (hemp plant). The plant produces many extracts that contain chemicals. The whole plant or its extracts can help control or relieve medical or mental health conditions. The medicinal use of cannabis is also called medical marijuana. 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. The effects may start right away and last for 3 to 4 hours.

What medical conditions or symptoms can cannabis help 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

What do I need to know about cannabis?

Cannabis can vary in quality and strength. Some people may find it helpful, while others may not. The right amount of cannabis needed, the best time to take it, or if it is working may not be clear.
Cannabis taken during pregnancy may affect an unborn baby's growth and development. Cannabis stays in fat cells and can slowly be transferred to the baby over time.
Cannabis may make you feel tired, drunk, dizzy, or high. It may worsen the symptoms it is used to relieve. Cannabis can cause anxiety, confusion, decreased memory, or difficulty learning. You may have an increased risk for panic disorder or depression. You may also see or hear things that are not real (hallucinations).
Cannabis withdrawal can happen if you stop using it. You may want to start again to relieve or prevent withdrawal symptoms, such as shaky hands. You may feel angry, anxious, nervous, or restless. You may lose your appetite, lose weight, or have trouble sleeping.
Cannabis may contain harmful substances, such as metals or fungus. You may have increased risk for a lung infection, long-term bronchitis, asthma, or other lung diseases. You may also have increased risk for head, neck, or lung cancer if you smoke cannabis. Cannabis may increase the risk for a heart attack or stroke.
Cannabis may affect nutrient absorption if you have liver problems. Cannabis may cause your liver to scar and not work properly.
Cannabis use may increase your risk for misuse. Misuse means you take more cannabis than prescribed. You may use it too often or for a different reason than recommended. For example, your prescription may be for pain relief, but you take it to feel good. You continue to use it even though it causes physical or social problems. This is also called cannabis use disorder.

What do I need to know about cannabinoids?

Cannabis produces chemicals called cannabinoids. The 2 main cannabinoids are called cannabidiol (CBD) and tetrahydrocannabinol (THC). These cannabinoids are separated from the rest of the marijuana plant. Cannabinoids are taken in different forms such as oils, capsules, mouth sprays, or patches.

THC is the chemical that causes a cannabis high. THC can affect parts of your brain that control nausea, appetite, memory, and focus.
CBD does not contain THC and does not cause a high. CBD can help with a substance use disorder or to relieve anxiety or depression. CBD may help relieve pain, decrease inflammation, and control muscle spasms. CBD may also help control some types of seizures.

What are cannabis safety guidelines to follow?

Take cannabis as directed. Do not increase the dose or how many times you take it on your own.
Ask your healthcare provider which type of cannabis is best for you. To support lung health choose non-inhaled cannabis forms such as oils, capsules, patches, or mouth sprays. Do not smoke or vape cannabis if you have respiratory problems such as asthma or COPD. Talk to your provider about non-inhaled forms of cannabis.
Do not drive or use heavy machinery. Cannabis can slow down your thinking and reactions.
Do not mix cannabis with alcohol, medicine, or drugs. This may increase dizziness, drowsiness, and the risk for accidents or falls.
Follow-up with your provider as directed. Your provider may want to check if cannabis is working for you. Your provider will make sure cannabis does not affect other medicines you take.
Store cannabis in a safe place. Keep cannabis away from children and pets.

Where can I find more information?

Substance Abuse and Mental Health Services Administration (SAMHSA)
PO Box 2345
Rockville , MD 20847-2345
Web Address: http://www.samhsa.gov or https://dpt2.samhsa.gov/treatment/

National Institute on Drug Abuse
6001 Executive Boulevard, Room 5213
Bethesda , MD 20892-9561
Phone: 1- 301 - 443-1124
Web Address: www.nida.nih.gov

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

You have sudden trouble breathing or chest pain.
You have thoughts of harming yourself or others.

When should I call my doctor?

You have changes in mood or behavior.
You have hallucinations.
Your symptoms do not improve.
You feel you are becoming addicted to or dependent on cannabis.
You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. 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.

Medical Disclaimer