The importance of consulting your doctor before taking complementary medicine

The importance of consulting your doctor before taking complementary medicine


Complementary medicines are medicinal products containing such ingredients as herbs, vitamins, minerals, nutritional supplements, homoeopathic and certain aromatherapy preparations.

According to a European study, complementary medicine is used by 35.9 per cent of people with cancer. This figure is estimated to be between 7 per cent and 54 per cent in the United States. Herbal medicines, homeopathy, vitamins/minerals, and medicinal teas are commonly used in an attempt to boost the body’s ability to fight cancer or reduce the side effects associated with treatment.

Nancy Meyers, a cancer patient, said every person in her cancer support group uses some kind of alternative medicine. She said, “I have plenty of friends in this cancer journey who I’ve met who take supplements. A lady I met recently takes 75 supplements a day. It takes her two hours to package her supplements every week”.

Complementary medicines are widely available without prescriptions, and are typically assumed to be safe when they come from ‘natural’ products. Well-meaning people may also encourage the use of these products on the basis that they can only help and it doesn’t hurt to try since they are supposedly safe.

Are complementary medicines helpful?

Some products have been tested in clinical trials and have been shown to help manage specific side effects of cancer treatment. For example, American ginseng and Astragalus root used in traditional Chinese medicine may help to reduce fatigue. Supplements such as glutamine, vitamin B6, vitamin E, and omega-3 have been tested as treatments for peripheral neuropathy. However, they are not appropriate for everyone, and more research is needed to confirm their safety and effectiveness. It is important to talk to your doctor before trying such products.

Are they safe?

Although complementary medicines are made from ‘natural’ products, it is important to remember that they may contain ingredients that could interfere with your cancer treatment or prescribed medications, and can lead to increased toxicity. Some examples include:

  • antioxidant supplements may make chemotherapy and radiation therapy less effective.
  • taking the herbal supplement ginkgo while receiving a blood thinner like warfarin can increase your risk of bleeding.
  • St. John’s Wort (a common supplement taken to treat depression, anxiety and sleep disorders) has the potential to cause a dangerous interaction with chemotherapy medications.
  • B17 which is sometimes touted without proof as a cancer fighter, can have a poisoning effect on the body” because of an inherent chemical ingredient, amygdalin, which turns into cyanide in the stomach.
  • Even something as innocuous as green tea has been shown to stop the cancer drug Bortezomib (brand name Velcade) from working properly.

In a study of breast cancer patients in the Journal of Clinical Oncology in 2019, iron taken during chemotherapy was associated with a higher rate of cancer recurrence, and vitamin B12 taken before and during chemotherapy was associated with a negative effect on survival.

Another study conducted at Cancer Treatment Centre of America showed that 25 per cent of patients receiving chemotherapy and using dietary supplements at the same time were suspected to have adverse interactions. Alarmingly, 53 per cent of the overall patients studied had not consulted their doctors about their supplement use.

In Summary

It is essential to tell your doctor and healthcare team of all medicines (prescribed as well as complementary ones), treatments and remedies you take or use.

It is also important to be aware and avoid health frauds. Scammers often also target cancer patients with the promise of miracle cure containing a ‘secret ingredient’ or a ‘propriety blend’. If it sounds too good to be true, it probably is.

Catherine has been volunteering with Peter MacCallum Cancer Centre since 2017, and joined Solaris Cancer Care as a blog writer in early August 2020. She cared for her father and her husband with cancer, and the experiences changed her life. Catherine developed a passion for researching all matters relating to cancer during her husband’s fight, and is keen to continue building on her knowledge and using it to help others.