Herbal medicines are biologically active preparations, and “natural” does not automatically mean risk-free. Some herbal products can alter the effects of prescription medicines, add to their side effects, or be unsuitable in particular circumstances. This page explains how we approach those risks at Riverside Natural Health Centre and what you should tell us before using herbal medicine.
This information is educational. It is not a substitute for urgent medical assessment, diagnosis or advice from your GP, pharmacist or another appropriate healthcare professional.
Can herbal medicines interact with prescription medicines?
Yes. Herb–drug interactions are a genuine part of safe herbal practice. The NHS advises people to check before taking herbal medicines if they already use medicines from a doctor or pharmacy, because some combinations can cause harmful effects or reduce how well a medicine works. Examples highlighted by the NHS include some statins, antidepressants, medicines for diabetes or high blood pressure, blood-thinning medicines and hormonal contraception.
Read the NHS guidance on herbal medicines and complementary therapies.
Who should be especially cautious?
Safety depends on the individual herb, preparation, dose and person taking it. Extra care is particularly important if you:
- take prescription or over-the-counter medicines;
- are pregnant or breastfeeding;
- have liver or kidney problems;
- have a history of reactions to medicines, foods or plants;
- use several medicines or supplements at the same time; or
- are considering a herbal product for a child.
The NHS specifically advises caution around pregnancy, breastfeeding, children, kidney or liver problems and concurrent medicines. In these situations, “it is herbal” is not a sufficient safety argument.
What we review during a herbal medicine consultation
A proper safety review is more than asking whether you take tablets. We may ask about prescription medicines, pharmacy medicines, supplements, previous reactions, allergies, relevant diagnoses, recent investigations and changes to your treatment. If you know the names and doses of your current medicines, bring an up-to-date list to your appointment.
Where a potential interaction or contraindication is identified, the sensible response may be to choose a different herb, alter the proposed preparation, defer herbal treatment, or ask you to check something with your pharmacist or medical team. Herbal treatment should not depend on pretending uncertainty does not exist.
What does “interaction checking” actually mean?
Interaction checking is not a promise that every possible interaction can be predicted. Evidence varies enormously between herbs. For some combinations there are documented clinical interactions; for others there may be laboratory or pharmacological reasons for caution but limited human data.
We therefore distinguish between:
- documented interactions reported in people or recognised medicine information;
- plausible interactions suggested by pharmacology or laboratory evidence;
- traditional cautions recorded in established herbal practice; and
- unknowns, where good evidence simply does not exist.
This distinction matters. Absence of a published interaction is not the same thing as proof that a combination is safe.
Are registered herbal products proven to work?
Not necessarily. In the UK, some traditional herbal medicinal products are marketed under the MHRA’s Traditional Herbal Registration (THR) scheme. A THR relates to standards including quality, safety and evidence of traditional use for appropriate minor conditions. It should not be interpreted as proof that effectiveness has been established through clinical trials.
The MHRA also distinguishes commercially marketed traditional herbal medicinal products from certain preparations supplied by a herbal practitioner following a one-to-one consultation. You can read the current regulatory guidance directly from the regulator:
MHRA guidance on Traditional Herbal Registration.
Herbal medicines, supplements and medicines are not all the same thing
A shop-bought supplement, a registered traditional herbal medicinal product and an individually prepared herbal prescription may all contain plants, but they are not necessarily regulated, formulated or used in the same way. Product strength, extraction method, plant part, dose and combination can all matter.
For an introduction to the different preparations used in herbal practice, see our guide to herbal medicine types and preparations. For the broader background, visit What is herbal medicine?.
What if I think I have had a reaction?
If you develop a suspected reaction, stop and seek appropriate medical advice rather than trying to “push through” it. Severe or rapidly worsening symptoms require urgent medical attention. If you are worried but it is not an emergency, contact your GP, pharmacist or NHS 111.
Patients and healthcare professionals can also report suspected adverse reactions to herbal medicines through the MHRA Yellow Card Scheme. These reports help regulators identify safety signals that may not have been recognised previously.
Report a suspected reaction through the MHRA Yellow Card Scheme.
Should I stop my prescribed medicine before taking herbs?
No—not unless the clinician responsible for that medicine tells you to do so. Herbal medicine should not be used as a reason to stop, reduce or replace prescribed treatment without appropriate medical advice.
What should I bring to my appointment?
- An up-to-date list of prescription medicines and doses.
- Any over-the-counter medicines you use regularly.
- Vitamins, minerals, protein powders and other supplements.
- Herbal products you are already taking, including teas and tinctures.
- Details of known allergies or previous adverse reactions.
- Relevant letters, test results or medication changes if you have them available.
Our approach at Riverside
We treat safety as part of the clinical process, not as a disclaimer at the bottom of a page. A herbal consultation is an opportunity to look at what you are already taking, what you hope to achieve, where the evidence is strong or weak, and whether herbal medicine is appropriate at all.
Sometimes the safest recommendation is a herbal preparation. Sometimes it is a different preparation. Sometimes it is to speak to your pharmacist or GP first. And sometimes the answer is that herbal treatment is not appropriate. That is a feature of responsible practice, not a failure of it.
Continue exploring
- Herbal Medicine at Riverside Natural Health Centre
- What is herbal medicine?
- Types and preparations of herbal medicine
- Meet Martin Eddy
Considering a consultation? You can view current Herbal Medicine appointment availability and booking information.