The Risks of Natural Medicines in Conjunction with Polypharmacy

In my practice, I often see people who are taking multiple prescribed medications for ongoing health conditions. At the same time, they’re also keen to use natural medicines, whether it’s herbal supplements, nutritional supplements, or other natural remedies.

This makes sense: natural medicines can support wellbeing, ease side effects, and sometimes fill gaps where conventional treatments fall short. But when someone is already on a handful of prescriptions, what we call polypharmacy, adding natural medicines isn’t always straightforward.

The key is balance. While it’s potentially unhelpful (and even unsafe) to take supplements without understanding the risks of interactions, it’s equally unhelpful to be told to “stop everything” just to be on the safe side. With the right guidance, natural and conventional medicines can work together safely and effectively.

What is Polypharmacy?

Polypharmacy is generally defined as the use of five or more medications at the same time. It’s common in older adults, but it also affects younger people living with chronic conditions such as diabetes, heart disease, or mental health challenges.

The more medications you take, the more complex the picture becomes. Each drug has its own effects, side effects, and metabolic pathways. When they’re combined, there’s potential for overlapping side effects, reduced effectiveness, or unexpected interactions.
When natural medicines are added into this mix, the potential for complications increases again.

Why Natural Medicines Aren’t Always “Safe”

Many people assume natural remedies are harmless because they’re plant-based or sold over the counter. But quality natural medicines are pharmacologically active, meaning they act on the body in the same way that drugs do.
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This is exactly why they can be so helpful when used correctly. But it also means they can interfere with prescription medications, sometimes in significant ways.

Common Interactions Between Natural and Prescription Medicines

Here are just a few well-documented examples:

St John’s Wort – often used for low mood, but it speeds up the breakdown of many drugs in the liver. This can reduce the effectiveness of some medications, including oral contraceptives

Licorice root – often used for digestion or adrenal support, but in higher doses it can raise blood pressure and interact with diuretics or corticosteroids.

Kava – sometimes taken for anxiety or insomnia, but it can increase sedation when combined with medications such as sleeping pills, benzodiazepines, or antidepressants.

​Schisandra – a traditional adaptogenic herb, but it can alter liver enzyme activity and therefore affect the metabolism of various medications.

The Hidden Risk: Self-Prescribing

One of the biggest risks I see is self-prescribing. Supplements are easily purchased from health shops, pharmacies, or online, and many people don’t mention them to their doctor or naturopath.

The problem is that without full visibility, no one is keeping track of the whole picture. I’ve met clients who were unknowingly doubling up on the same nutrient in multiple formulas, or taking herbs that directly interfered with their medication.

​At the same time, it’s not helpful when people are told to stop all natural medicines out of caution. This can mean missing out on valuable support. The real solution lies in working with a practitioner who understands these interactions.  Someone who can help you use natural medicines safely, in a way that complements your prescriptions rather than complicating them.

Safe Use of Natural Medicines with Polypharmacy

So how do we keep natural medicines safe and beneficial in the context of polypharmacy?
Here are some key principles:

1. Full disclosure matters – Always let your healthcare providers know exactly what you’re taking, including natural products, vitamins and minerals. Transparency allows for safer decisions.
2. Work with a practitioner who understands both sides – A naturopath who is comfortable reading blood tests and medication lists can help identify what is safe and what is not.  Collaboration with your GP is ideal.
3. Evidence before trends – Choose natural medicines with good research backing, rather than whatever is currently popular online or in health stores.
4. Ask the right questions – “Do I really need this supplement? Could I get the same support from diet or lifestyle changes? Will this add something useful, or just complicate things?”
5. Start low and monitor – If a natural medicine is added, it should be introduced slowly, with close monitoring for changes in symptoms, side effects, or test results.

When Natural Medicines Can Be Helpful

It’s important to balance this discussion by acknowledging the benefits natural medicines can bring, especially when used carefully. For example:

Magnesium can ease muscle cramps or constipation without clashing with most prescriptions.

Ginger can help with nausea, including in people undergoing chemotherapy, when dosed appropriately.

​Probiotics may support gut health during or after antibiotic use.

​When selected and monitored appropriately, natural medicines can improve quality of life and support overall health, even in the context of polypharmacy.

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The Take-Home Message

Natural doesn’t always mean risk-free. In the context of polypharmacy, even small additions can tip the balance and create unintended consequences.

But that doesn’t mean natural medicines should be avoided altogether. It means they should be used thoughtfully, with professional guidance, and in full awareness of the bigger health picture.

Being told to “stop everything” is just as unhelpful as taking multiple supplements without considering the risks. The best approach lies in between:  Seek advice from a professional who understands these interactions and can support you safely.

​With open communication and careful planning, natural and conventional medicine can complement each other beautifully, supporting health in a way that is safe, personalised, and effective.

Contact SmartGENES Naturopathic Clinic

​Vanessa Winter
​Naturopath & Medical Herbalist
BHSc (Deans Award for Academic Excellence), BED, Adv.Dip.Nat., Adv.Dip.Herb.Med., NMHNZ
​Registered with Naturopaths and Medical Herbalists of NZ (NMHNZ)