Skip to main content

Natural Health Products

Revised: January 2006

Joint Recommendation from the BC Cancer Departments of Medical Oncology, Radiation Oncology, Surgical Oncology, Pharmacy, Nursing and Nutrition

The use of natural health products during chemotherapy, radiation therapy or surgery is not recommended.

Natural health products are vitamins, minerals, herbs and other supplements that you take on a regular basis as a natural medicine in addition to what you get from food. They are sometimes taken in higher amounts than can be obtained through your diet.

A regular strength multiple vitamin and mineral supplement is acceptable. Select a brand that is specific to your age group. The supplement should contain small doses of a wide variety of nutrients (high doses are not recommended).

Your doctor cannot predict the effect of taking natural health products during cancer treatment. Chemotherapy drugs and radiation therapy attack cancer cells in a variety of ways that are complex and not fully understood. Cancer therapies are developed to maximize damage to the cancer cells while minimizing damage to healthy cells. Natural health products could change this and prevent your treatment from achieving the desired effect, or increase side effects.

Natural health products may affect the way your body handles chemotherapy drugs. For example, St. John's Wort reduces the amount of one chemotherapy drug in the blood by about half. As a result, fewer cancer cells may be destroyed.

Your doctor needs scientific proof to be sure that it is safe for you to take natural health products during cancer treatment. It is important to compare groups of people in a research study to find out the effects of taking natural health products during cancer therapy. At present, these studies are not generally available, and the safety or benefit of taking natural health products during cancer treatment is unknown.

Food sources usually do not need to be restricted during cancer treatment. Your cancer care team will tell you if there are certain foods to avoid during treatment.

For more information on diet, please consult with a registered dietitian at your cancer treatment centre.

These recommendations provide guidance on the safety of using natural health products. This is a controversial area because of the limited amount of scientific information that exists at this time. Please contact your doctor, pharmacist, nurse or dietitian for further discussion. Additional information may be obtained from the BC Cancer Library and from the internet (this website and


Weiger WA, Smith M, Boon H, et al. Advising patients who seek complementary and alternative medical therapies for cancer. Ann Intern Med 2002;137:889-903.

SOURCE: Natural Health Products ( )
Page printed: . Unofficial document if printed. Please refer to SOURCE for latest information.

Copyright © BC Cancer. All Rights Reserved.

    Copyright © 2024 Provincial Health Services Authority