Taking Complementary and Alternative Products with Your Medicines

- November 7, 2022


Key points:

  • There is far less information about how well complementary and alternative products work and how safe they are compared to medicines.
  • There are no rules in Aotearoa NZ to make sure the contents are what the label says. This makes it difficult to say whether they will react with medicines, so it is often safer not to take these products.
  • If you think you have had a reaction to a complementary and alternative product, it is a good idea to report it to Centre for Adverse Reactions Monitoring (https://nzphvc.otago.ac.nz/consumer-reporting/) 

What are complementary and alternative products?

Examples include herbals made from plants, rongoā rākau, dietary supplements, probiotics and homeopathic products. They may also be called natural or herbal medicines. When used with a medicine prescribed by your doctor it’s considered complementary; when it is used instead of a medicine it’s considered alternative.

What are the risks with use?

Complementary and alternative products do not have to be studied to make sure they are safe and effective. Recent studies have found some products do not always contain what is on the label or may have other things in them such as contaminants, pesticides or bacteria. The quality of the product is not assessed by our government group called Medsafe which assesses medicines.

Using these products instead of treatments recommended by your doctor can slow down or prevent you becoming well. Using them with the treatments prescribed by your doctor can reduce the medicine’s effectiveness or cause increased side effects.

If I decide to use them, who needs to know?

Let your doctor, nurse or pharmacist know if you are taking or want to take a complementary and alternative product. They may be able to discuss any potential benefits of use, check interactions with medicines you take, and let you know about any known safety concerns. However, there is usually very little information about side effects and interactions to go by, so your health professional may not recommend using them.

If you really want to try a product, we suggest trialling for a fixed amount of time (e.g. a couple of months) and then stopping if you do not notice any benefit.

What if I experience side effects?

All complementary and alternative products have a potential to cause side effects, even natural substances derived from plants, and these may be serious. If you think you have experienced a concerning side effect, we suggest reporting it to the Centre for Adverse Reactions Monitoring (https://nzphvc.otago.ac.nz/consumer-reporting/)  and tell your health professional.

This leaflet has been produced by the Clinical Pharmacology department at Te Whatu Ora/Health NZ (Waitaha Canterbury) on 8 Nov 2022.

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