Medicinal cannabis, explained

There is a lot of interest in the use of cannabis as a medicine. You may have questions about the new products and how they are used.

Find out more.


What is medicinal cannabis?

Cannabis is a plant from the hemp family. Humans have been growing cannabis and using it in many ways for thousands of years.

People often use chemicals found in the cannabis plant to make medicinal cannabis. These are phytocannabinoids (in Greek, ‘phyto’ means ‘of a plant’).

Medicinal cannabis products made in a lab copy the actions of these chemicals that exist in nature. These lab-made products are called synthetic (man-made) cannabinoids.

Some man-made cannabinoids are more harmful that the cannabinoids found in nature. They have unwanted effects that can be toxic and even life-threatening.

How does medicinal cannabis work?

Cannabis plants have chemicals called phytocannabinoids (also called cannabinoids). There are more than 100 different types found in cannabis plants.

Our bodies also make cannabinoids. They are called endocannabinoids and they can have an effect on:

  • feelings of hunger, 
  • sleep, 
  • memory, 
  • pain 
  • redness and swelling (inflammation).

In our body, cannabinoids from the cannabis plant can work in a similar way to endocannabinoids . 

Two of the most common cannabinoid compounds used in medicinal cannabis products are THC (delta 9-tetrahydrocannabinol) and CBD (cannabidiol). Research is looking at how CBD and THC can help treat different illnesses and conditions. For example using CBD and THC together may help manage some fits (seizures). The compounds might also help some people who live with pain or anxiety.

THC is the compound that can cause the ‘high’ some people have when using recreational cannabis. It can:

  • stop you feeling like you need to throw up (nausea), 
  • stop or reduce vomiting, 
  • reduce feelings of pain,
  • reduce muscle tightness that causes spasms,
  • improve sleep and 
  • make you feel hungry. 

CBD does not cause a ‘high’. It can decrease unwanted side effects of THC like: 

  • diarrhoea, 
  • feeling confused, 
  • seeing things that are not really there (hallucinations),
  • having untrue thoughts (psychosis). 

    Medicinal cannabis is not ‘first-line’ treatment for any health condition. It is an option when other approved treatments have been tried and not worked.

    Is medicinal cannabis the same as recreational cannabis?

    No. Medicinal cannabis is not the same as recreational cannabis (also known as marijuana). It is treated like a medicine and must:

    • follow Australian standards for making pharmaceutical-grade medicines
    • meet strict Australian quality and safety standards
    • contain known amounts of the cannabinoids THC and CBD
    • not contain any moulds, fungi, bacteria, pesticides, heavy metals or other substances that can be harmful to a person.

    What are some of the approved conditions for medicinal cannabis treatment?

    In Australia, the Therapeutic Goods Administration (TGA) approves requests for people to use medicinal cannabis. Approvals have been given for people who:

    • feel like throwing up (nausea) or throw up (vomiting) after cancer treatment
    • are children who have seizures because of hard to manage epilepsy
    • are at end-of-life 
    • have hard to control cancer pain
    • have hard to treat nerve pain
    • have muscle tightness from conditions such as multiple sclerosis
    • have lost a lot of weight and are unable to eat because of a long-term illness such as cancer.

    Find out more about how medicinal cannabis may be helpful on the TGA website.

    Who can prescribe medicinal cannabis?

    Medicinal cannabis is subject to laws and rules in Australia.

    It is not ‘first line’ treatment for any medical condition.

    Your doctor may think about prescribing medicinal cannabis after you have tried all other usual approved options and they have not helped. Before they prescribe medicinal cannabis your doctor should read the available research to help them decide if it may work for you.

    Before they can prescribe medicinal cannabis your doctor will need to get government approval. There may be more than one type of approval needed.

    Download our guide to the approval process and how to access medicinal cannabis


    Your doctor can download our guide to the process for prescribers

    How do I take medicinal cannabis?

    Medicinal cannabis is not a ‘first line’ treatment for any health condition. Your doctor should only think about prescribing it if the usual approved treatments have not worked.

    Before starting any medicine, ask your doctor or pharmacist for information about:

    • how much to take, 
    • how to take it 
    • what the unwanted effects might be.

    If your doctor prescribes medicinal cannabis, always take the dose (amount) they tell you.

    There are a number of different medicinal cannabis products available.

    • some are sprayed into the mouth or under the tongue
    • some are oils, liquid capsules or tablets that you swallow
    • some need to be heated so a vapour or steam can be breathed in.

    There are many vaporisers (heating devices) available. Most are not approved by the TGA for use with medicinal cannabis. Before using a device ask your doctor about which ones have been tested and are safe to use. Your doctor can also check with the TGA about vaporisers that have been approved.

    You should not smoke cannabis products. Smoking can raise your risk of getting cancer, stroke, heart disease and other severe health conditions.

    What are the unwanted effects of medicinal cannabis?

    Like all medicines, medicinal cannabis products can have unwanted effects. These are also called side effects and include:

    • feeling tired all the time
    • feeling sleepy
    • feeling dizzy
    • feeling confused
    • feeling like you need to throw up (nausea)
    • having a fever
    • changes to how hungry you are
    • having a dry mouth, and
    • needing to empty your bowels more often (diarrhoea).

    People who take medicinal cannabis products that have a high amount of THC may have the following side effects:

    • feeling ‘high’ 
    • feeling deeply sad or depressed
    • feeling confused
    • feeling, hearing, tasting, smelling or seeing things that are not really there (hallucinations)
    • having a false belief that other people may wish to cause harm
    • having trouble knowing what is real and what is not
    • having thoughts that are not true.

    How much medicinal cannabis you take can affect what types of side effects you have. Always follow the instructions given to you by your doctor.

    Do not take these products without speaking with a health professional. Other medicines can be affected by medicinal cannabis and not work properly, or cause more side effects.

    What should I do if I get side effects?

    If you have an unwanted effect after taking medicinal cannabis get in touch with you doctor as soon as possible. You should do this if you have unwanted effects after taking any medicine. 

    If you suddenly feel very unwell or have trouble breathing after taking a medicine call 000 and ask for an ambulance. Or ask someone to take you straight to the closest hospital Emergency Department.

    If you think you may have taken too much medicine or taken something that you shouldn't have, you can call the Poisons Information Centre 24 hours a day on 13 11 26.

    You can also call Medicines Line if you have general questions about your medicines and possible side effects. 

    • 1300 MEDICINE (1300 633 424) from anywhere in Australia.  
    • Monday to Friday, 9am to 5pm AEST (excluding NSW public holidays)

    What are the risks of buying medicinal cannabis online?

    Australia has a very good system to make sure medicines sold here are safe and high quality. The government body that looks after this system is the Therapeutic Goods Administration (TGA). 

    The TGA has created rules to make sure medicinal cannabis is treated like a medicine so it is safe for people to use, if their doctor prescribes it.

    Even if you have an authorised prescription, it is against the law for you to personally order medicinal cannabis products. This includes ordering online or importing from overseas for personal use.

    The Office of Drug Control can give doctors or pharmacists a license to import.  

    Medicines that can be ordered from overseas and are not regulated by the TGA can be risky to use.

    • They may be fake, with ingredients that do not work the way you expect them to.
    • They may have the correct ingredients, but not in the correct amounts. Not enough makes the medicine weak and not able to work in the right way. Too much medicine puts you at risk of bad effects that could leave you more unwell.  
    • They may have other chemicals that are toxic or dangerous.

    For more information download our medicinal cannabis FAQs

    Where can I go for more information?