• Complementary medicines can cause unwanted effects as well as beneficial effects.
  • It is important to tell all your healthcare professionals about all the medicines you are taking, including complementary medicines.
  • Discuss the possible benefits and harms of using complementary medicines with your healthcare professionals before you start taking them.

Complementary medicines include vitamin and mineral products, herbal medicines including Chinese and Ayurveda medicines, homeopathic preparations and essential oils.

It is important to tell all your healthcare professionals about any complementary medicines you are taking. This is because complementary medicines can interact with other medications, and can increase the risk of side effects – for example when undergoing surgery, when pregnant, and when experiencing other health conditions.

Complementary medicines can interact with other medicines

People often think complementary medicines are safe and will not cause any problems because they come from natural sources. This is not always the case. Natural substances still have the potential to be harmful. And, while the source of some complementary medicines is natural’, the products themselves may be manufactured in similar ways to conventional medicines.

Complementary medicines can cause side effects. They can also interact with prescription medicines, alcohol and other drugs, and other complementary medicines to cause side effects. 

For these reasons, it’s important to tell all your healthcare professionals about all the medicines you are taking, including prescribed medicines, over-the-counter medicines and complementary medicines. 

For example, some complementary or alternative medicines can interfere with cancer treatments. If you are about to receive chemotherapy, talk to your oncologist or haematologist about any other therapies or medicines you are taking or thinking of trying. Tell other health professionals (for example, nurses or pharmacists) at your treatment centre before starting treatment if you are taking complementary medicines.

Interactions with prescription medicines

Interactions between complementary medicines and prescription medicines can occur. For example, the medicines may have similar active ingredients that act in the same way, or the complementary medicine may increase or reduce the effectiveness of the prescription medicine.

Some interactions between complementary medicines and prescription medicines that can put people’s health at risk include: 

  • Echinacea may interact with medications broken down by the liver. 
  • Many complementary medicines – including feverfew, ginkgo and chamomile – may increase the risk of bleeding in people taking anticoagulant medicines such as warfarin and anti-inflammatory medicines such as aspirin.
  • St John’s wort has caused breakthrough bleeding and unwanted pregnancy in women taking the oral contraceptive pill. 
  • St John’s wort increases serotonin. Taking St John’s wort at the same time as other medicines that increase serotonin (such as antidepressants) increases the risk of serotonin toxicity (serotonin syndrome) – symptoms include tremors, high temperature and low blood pressure and can range from mild to life threatening. 

Side effects of complementary medicines

Some examples of complementary medicines that can cause side effects include: 

  • echinacea – over 20 different types of side effects have been reported, including asthma attacks, hives, swelling, aching muscles and gastrointestinal upsets
  • feverfew – pregnant women are cautioned against using this herb because it can trigger uterine contractions. In animal experiments, feverfew was found to trigger spontaneous abortions (miscarriages)
  • asteraceae plants (from the daisy family, including feverfew, echinacea, dandelion and chamomile) – side effects include allergic dermatitis and hay fever.

The way some complementary medicines are applied or used also needs to be considered, because side effects may be caused by the way the medicine is used, rather than the medicine itself. 

For example, some people who take anticoagulant medicines (blood thinners) after an essential oil massage have reported significant bruising. In this case, it was most likely the massage, rather than the essential oils, that was the cause of the bruising.

Why people don’t report using complementary medicines

About half the people who use complementary medicines do not tell all their healthcare professionals. The reasons for this include: 

  • not thinking of complementary medicines as ‘medicines’
  • thinking that products promoted as ‘botanical’ or ‘natural’ are safe and not likely to cause side effects
  • believing their healthcare professionals are either not interested or will not understand why they use complementary medicines
  • feeling concerned that their healthcare professionals will be judgemental or negative
  • believing that healthcare professionals have limited knowledge about the effectiveness and potential benefits and harms of complementary medicines
  • not being asked by their healthcare professionals about complementary medicines. 

What your healthcare professionals need to know about the complementary medicines you use

If you don’t tell your healthcare professionals that you are using complementary medicines, you may put your health at risk. Give your healthcare professionals the following information: 

  • the type and name of any complementary medicines you are taking
  • how often you take the medicine and the dose
  • the amount of active ingredient in each dose – it may be easier to bring the medicine with you (you need to use the botanical names of herbal medicines and essential oils to avoid confusion caused by the common names)
  • how long you have been taking the medicine and why you are taking it
  • the health benefits that you expect from taking the medicine
  • whether the medicine has worked for you.

Make sure you tell your healthcare professionals about any changes to complementary medicines you are taking.

If you’re advised to stop using complementary medicine, ask why

Your healthcare professional may not support you taking the complementary medicine. If they advise you to stop taking it, ask why before you assume that they are biased against complementary medicines. There may be good medical reasons why you should not take a particular complementary medicine, such as when there is an increased risk of interactions with other medicines or side effects. 

Check with your doctor before using complementary medicines

Talk to your doctor about the benefits and risks of your chosen complementary medicine before you start taking it. It is important that you have a correct diagnosis before you treat any condition, otherwise the benefits of appropriate treatment might be delayed and put your health at risk.

People with certain health conditions are at greater risk of adverse reactions or complications than others if they use certain complementary medicines. People at high risk include:

  • pregnant women, especially in the first trimester
  • people with kidney or liver disorders
  • people who are already taking prescription medicines, non-prescription medicines or other complementary medicines
  • people taking multiple medicines
  • young children
  • older people
  • people who are malnourished – for example, people with anorexia
  • people who misuse alcohol or other drugs.

Surgery and tests and complementary medicines

If you are scheduled for any medical investigation or surgery, you may need to stop taking your complementary medicines or adjust the doses some time before the procedure is scheduled to take place. Ask your healthcare professional what to do about all your medicines if you need to have an investigation or surgery.

Choose complementary medicines carefully

For your safety and effectiveness of treatment, it is recommended that you avoid self-prescribing any medicine, including complementary medicines. Always see a registered health practitioner. 

If you decide to buy complementary medicines ‘over the counter’, read the labels on all packages and containers. Select products that are manufactured to Australian standards and have an Aust L or Aust R number on the package. This means the medicine meets Australian manufacturing and safety standards and is less likely to be contaminated.

Medicines purchased in other countries or purchased on the internet may not be manufactured to the same standard.

Where to get help

  • In an emergency, call triple zero (000)
  • Your doctor
  • Nurses, especially specialist nurses such as diabetes educators or cancer nurses
  • Pharmacists
  • Other healthcare professionals, such as registered complementary therapists
  • Medicines Line Tel. 1300 MEDICINE (1300 633 424) – for information on prescription, over-the-counter and complementary medicines 
  • Adverse Medicine Events (AME) Line Tel. 1300 134 237 – to report and discuss possible side effects from your medicine
  • Victorian Poisons Information Centre Tel. 13 11 26 – seven days a week, 24 hours a day – for advice about poisonings, suspected poisonings, bites and stings, mistakes with medicines and poisoning prevention advice.
  • NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)

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  • Complementary medicines, NPS MedicineWise. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Complementary medicines, Therapeutic Goods Administration, Australian Government Department of Health. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Echinacea, 2013, Mayo Clinic, USA. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Echinacea, NPS MedicineWise. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Kreijkamp-Kaspers S, McGuire T, Bedford S, et al. 2015, ‘Your questions about complementary medicines answered’, Australian Family Physician, vol. 44, no. 6, pp. 373–374. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Making treatment decisions, 2015, Cancer Council Victoria. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Steel A, Adams J, Sibbritt D, et al. 2014, ‘Relationship between complementary and alternative medicine use and incidence of adverse birth outcomes: An examination of a nationally representative sample of 1835 Australian women’ , Midwifery, vol. 30, no. 12, pp. 1157–1165. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.
  • Talking with your patients about complementary medicine – a resource for clinicians, 2014, National Health and Medical Research Council, Australian Government. Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.

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Complementary and alternative care

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Last updated: December 2016

Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances. The State of Victoria and the Department of Health & Human Services shall not bear any liability for reliance by any user on the materials contained on this website.