Herbal medicine is the use of plant-derived substances and preparations within healthcare. That simple definition hides a surprisingly technical subject. The identity of the plant, the part used, how it is processed, the extraction method, the dose and the person taking it can all change what a herbal preparation actually does.
At Riverside, we do not present herbal medicine as “nature versus medicine”. Many modern medicines began with compounds discovered in plants, while many herbal preparations contain dozens or hundreds of constituents rather than one isolated molecule. The useful question is not whether something is natural or synthetic; it is what it contains, what evidence exists, what risks are known, and whether it is appropriate for the individual.
How is a herbal medicine defined?
UK medicines regulation uses a more precise definition than everyday language. The MHRA describes a herbal medicinal product as one whose active ingredients are herbal substances, herbal preparations, or both. A herbal substance may be a plant or plant part, but the regulatory definition can also include materials such as algae, fungi, lichens and certain unprocessed exudates. A herbal preparation can involve processes such as extraction, distillation, expression, purification, concentration or fermentation.
That matters because “herbal medicine” is not synonymous with “a cup of tea”. A tincture, dry extract, infusion and essential oil made from the same species can differ substantially in composition and concentration.
Read the MHRA definition and Traditional Herbal Registration guidance.
A plant is a chemical system, not a single ingredient
Plants produce a wide range of primary and secondary metabolites. Depending on the species, these may include alkaloids, terpenes, phenolic compounds, flavonoids, tannins, volatile oils and many other chemical families. Some have well-characterised biological activity; others are poorly studied; many occur together in complex mixtures.
This complexity is one reason it is misleading to talk about a herb as though it were one molecule. It is also why the exact plant material matters. Different species can share a common name, different parts of one plant can contain different constituents, and extraction methods may preferentially concentrate different chemical groups.
Why does the plant part matter?
Leaves, roots, bark, flowers, fruits, seeds and resins are not automatically interchangeable. The medicinally used part is chosen because its chemical profile and traditional or documented use differ from other parts of the same plant.
A good herbal label or prescription therefore needs more than a common name. Botanical identity, plant part and preparation are central pieces of information. This becomes particularly important when reading research: a clinical trial on one standardised extract cannot automatically be used as evidence for every tea, tincture or supplement made from that plant.
How are herbal medicines prepared?
Common preparations include infusions, decoctions, tinctures, fluid or dry extracts, powders, capsules and external preparations such as creams or oils. Each has practical advantages and limitations. Water extracts different constituents from alcohol; heat can alter some compounds; concentration ratios vary; and a preparation that is convenient for one person may be unsuitable for another.
Our Types and preparations of herbal medicine page explains the main forms in more detail.
Where does traditional knowledge fit?
Herbal medicine exists within many traditions, including Western herbal medicine, Chinese herbal medicine, Ayurveda and numerous regional or Indigenous systems. Historical use can tell us which plants were valued, how they were prepared and what observations accumulated over generations.
Traditional use is meaningful evidence about history and practice, but it is not identical to modern clinical evidence. A remedy can have a long history and still lack high-quality trials. Conversely, modern research may identify effects, risks or interactions that were not visible to earlier practitioners.
We think the intellectually honest approach is to preserve traditional knowledge without pretending its evidential status is something it is not.
How is evidence for herbal medicine assessed?
Different questions require different kinds of evidence. Laboratory studies may help explain mechanisms. Animal studies can generate hypotheses but do not establish clinical effectiveness in people. Observational evidence can identify associations. Randomised controlled trials and systematic reviews can provide stronger evidence for particular clinical questions, although their quality still varies.
For herbal medicines there is an extra complication: preparation-specific evidence. The European Medicines Agency’s Committee on Herbal Medicinal Products (HMPC) publishes European Union herbal monographs covering particular herbal substances and preparations. These may distinguish between well-established use, where sufficient safety and efficacy data exist for a marketing-authorisation route, and traditional use, where registration rests on sufficient safety information and plausible efficacy grounded in long-standing use.
Explore the European Medicines Agency’s information on herbal medicinal products and monographs.
Why “one study says…” is rarely enough
A headline about one positive study can be interesting, but it does not settle a clinical question. Useful appraisal asks:
- Was the study in humans?
- How many people took part?
- Was there an appropriate comparison group?
- Was the herbal preparation clearly identified and standardised?
- Was the outcome clinically meaningful rather than merely statistically significant?
- Were adverse effects and drop-outs reported?
- Can the result be replicated?
- Does the preparation studied resemble the product being discussed?
This is the approach we want the Riverside Herbal Medicine library to model. Research should be explained, not waved around as decoration.
What does a herbalist actually do?
A herbal consultation involves more than choosing a plant from a symptom list. The practitioner needs enough context to decide whether herbal medicine is appropriate at all. That can include medicines and supplements, allergies, previous reactions, relevant diagnoses and investigations, diet, sleep, stress, digestion and other aspects of health history.
If herbs are considered appropriate, the practitioner then has to think about formulation, preparation, dose, practical use, contraindications and possible interactions. In some situations the most responsible recommendation is to seek medical or pharmaceutical advice before adding anything new.
For Riverside’s consultation information, visit Herbal Medicine in Nottingham.
Is herbal medicine automatically safer because it is natural?
No. Natural origin does not guarantee safety. Plants can cause side effects, allergic reactions, toxicity and clinically important interactions. Risk depends on the substance, dose, preparation and individual.
The NHS advises people to check before using herbal medicines when they take other medicines, and highlights particular caution in pregnancy, breastfeeding, children, and people with kidney or liver problems. Our dedicated Herbal Medicine Safety and Interactions page explains this in detail.
Herbal medicine and conventional healthcare
There is no sensible reason to turn healthcare into a loyalty test between “natural” and “conventional”. A plant preparation can be useful in one context and inappropriate in another; the same is true of many conventional treatments. Good decisions depend on evidence, risk, individual circumstances and the clinical question being asked.
Herbal medicine should not be used as a reason to ignore serious symptoms, delay appropriate investigation or stop prescribed medication without advice from the clinician responsible for it.
What about quality?
Quality is not just about whether a product looks clean or has an attractive label. Relevant issues can include correct botanical identity, contamination, adulteration, extraction method, storage, stability and batch consistency.
In the UK, some traditional herbal medicinal products sold to the public carry a Traditional Herbal Registration (THR). The THR scheme considers quality, safety and evidence of traditional use for eligible products. It does not mean that clinical effectiveness has been proven through trials.
Frequently asked questions
Is herbal medicine the same as taking supplements?
No. Some supplements contain herbs, but supplements and herbal medicinal products can fall under different regulatory categories. Practitioner-supplied preparations are also not automatically equivalent to retail supplements.
Does a herb work the same way in everyone?
No. Dose, preparation, age, physiology, other medicines, health conditions and many other variables can affect both benefit and risk.
Are herbal medicines drug-free?
“Drug-free” is not a useful scientific description. Herbal preparations contain biologically active chemicals. The important questions are which constituents are present, at what concentration, and what is known about their effects and risks.
Can I research a herb myself?
Yes, but pay attention to the source and the exact preparation being discussed. Regulatory monographs, systematic reviews, medicine-safety information and primary research are generally more useful than commercial supplement pages repeating each other.
Where to go next
- Herbal Medicine at Riverside
- Types and preparations of herbal medicine
- Herbal Medicine Safety and Interactions
- About Martin Eddy
Considering a consultation? View current Herbal Medicine appointments and booking information.
This page is educational and does not provide individual diagnosis or treatment advice.