Glossary of Herbal Medicine Terms
Plain-language glossary of herbal medicine terms: plant names, teas, tinctures and extracts, regulator labels, research words and safety words, each tied to a source we read.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read herb safety and interactions before you use anything on this page.
This glossary explains the words you meet on herb labels, in health news and in regulator documents. Each entry says what the word means and, where it matters, what the word does not tell you. Definitions come from the sources listed at the end, so some everyday words (such as "adaptogen" or "detox") are left out because we did not read a source that defines them. The glossary describes terms only. It gives no preparation steps and no amounts.
Plants and names
| Term | Plain meaning | Worth knowing |
|---|---|---|
| Herb | MedlinePlus defines an herb as a plant or plant part used for its scent, flavor, or therapeutic properties. [1] | The same plant can be a food, a spice and a supplement ingredient. |
| Herbal medicine | MedlinePlus says herbal medicines are one type of dietary supplement and are sold as tablets, capsules, powders, teas, extracts, and fresh or dried plants. [1] | The word "medicine" does not mean it was tested like a drug. MedlinePlus says herbal medicines do not have to go through the testing that drugs do. [1] |
| Dietary supplement | NCCIH says federal law (US) defines dietary supplements by features such as being taken by mouth, made to supplement the diet, containing dietary ingredients such as herbs or other botanicals, and labeled as supplements. [2] | Applies to the United States. Other countries use other categories. |
| Herbal supplement or botanical | NCCIH says herbal supplements, sometimes called botanicals, are a type of dietary supplement containing one or more herbs. [2] | "Botanical" is used for herbs and other plant-derived ingredients. |
| Herbal substance | In the EU, plants, plant parts, algae, fungi or lichen in an unprocessed form, usually dried but sometimes fresh. The EMA says herbal substances are defined by the plant part used and the botanical name in the binomial system. [3] | Plant part matters: a result for a leaf does not describe a root. |
| Scientific (binomial) name | The two-part Latin name, genus then species, such as Sambucus nigra. The EMA uses the binomial system to define herbal substances. [3] | Common names can point to different plants. See Plant Names and Botanical Nomenclature. |
| Accepted name and synonym | A database lists one accepted name and may list older or alternate names as synonyms. In the GBIF record we read, Rhamnus purshiana has the status "synonym" and points to the species Frangula purshiana. [4] | A label may use an older name for the same plant. |
Forms and preparations
| Term | Plain meaning | Worth knowing |
|---|---|---|
| Herbal preparation | The EMA defines these as preparations obtained by treatments such as extraction, distillation, expression, fractionation, purification, concentration or fermentation. [5] | The EMA's list includes powdered herbs, tinctures, extracts, essential oils and expressed juices. [5] |
| Herbal medicinal product | The EMA defines this as any medicinal product exclusively containing, as active ingredients, one or more herbal substances or herbal preparations. [6] | An EU regulatory term. It is not the same as a US dietary supplement. |
| Herbal tea | Herbal teas are herbal substances meant for oral water-based preparations made by decoction, infusion or maceration. [7] | The EMA warns that different preparations may exert different actions and sometimes have a different safety profile. [7] |
| Infusion | A liquid made by pouring boiling water over the herb. [7] | The EMA says infusion is usually suited to leaves, flowers and delicate parts. [7] |
| Decoction | A liquid made by heating the herb in water and simmering it. [7] | The EMA says decoction or maceration usually suits roots, rhizomes and barks. [7] |
| Macerate and digestion | A macerate is made by soaking the herb in water at room temperature. With gentle warming that stops short of boiling, the process is called digestion. [7] | Terms only. We give no timings or steps. |
| Herbal tea mixture | A mixture of herbal substances. [7] | Blends can hide which plant a study applies to. |
| Tincture | In an EU herbal monograph, a tincture is listed with the ratio of herb to extraction solvent and the strength of the solvent. [8] | The monograph we read gives the example "Tincture (ratio of herbal substance to extraction solvent 1:5)". [8] |
| Liquid extract and dry extract | EU monographs list these with a "DER" ratio and the solvent used, for example "Liquid extract (DER 1:7-9)". [8] | The part of the monograph we read does not spell out "DER", so we do not define it. |
| Essential oil | The EMA lists essential oils as one kind of herbal preparation. [5] | Oils have their own safety rules. See Essential Oils. |
| Standardized | A label word. NCCIH says a maker's use of "standardized" (or "verified" or "certified") does not necessarily guarantee product quality or consistency. [9] | See Standardized Herbal Extracts Explained. |
| Bioavailable | Easier for the body to absorb. NCCIH says highly bioavailable curcumin formulations, which enhance the body's ability to absorb curcumin, may harm your liver. [10] | More absorbed is not automatically better. |
For how teas, tinctures, capsules and powders differ, see Herbal Teas, Infusions and Decoctions Explained and Tinctures, Fluid Extracts and Glycerites.
Research words
| Term | Plain meaning | Worth knowing |
|---|---|---|
| Placebo | NCCIH describes it as an inactive substance that looks like the drug or treatment being tested. [12] | In a randomized, placebo-controlled trial, volunteers are randomly assigned to a test group or a placebo group. [12] |
| Placebo effect | NCCIH defines it as a beneficial health outcome resulting from a person's anticipation that an intervention will help. [12] | One reason trials need a comparison group. |
| Systematic review | Cochrane says it attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a specific research question. [13] | Quality still depends on the studies reviewed. |
| Meta-analysis | Cochrane says combining the results of individual studies into one overall statistic is usually called a meta-analysis. [13] | Pooling different products can blur what one product does. |
| Preclinical research | The FDA describes preclinical research as the work done before testing a drug in people, to learn whether it could cause serious harm. [14] | On this site, "preclinical (cells or animals)" marks findings that are not human trials. |
Evidence labels used across this library are our own working labels, not terms from a source. They are established, promising but limited, mixed, insufficient evidence, no good evidence of benefit, evidence of harm, preclinical (cells or animals), traditional use only and marketing claim. "Proper evidence not found" means we searched named sources and found nothing usable. A "biomarker" is a lab or body measurement (for example a blood test) rather than how a person feels or functions. For more, see How to Read a Herb Study or News Headline.
Not covered here
Terms from Traditional Chinese Medicine, Ayurveda and other traditions (such as qi or dosha) are explained in Therapies and Traditions, because they carry their own meanings that a short entry would flatten. Names for adaptogens, mushrooms and essential oils are in their own libraries. For an A-to-Z list of safety words, see the Glossary of Safety Terms.
Frequently asked questions
What is the difference between an herb and a dietary supplement?
An herb is a plant or plant part used for its scent, flavor, or therapeutic properties. [1] A herbal supplement is a dietary supplement that contains one or more herbs. [2]
What does "standardized" on a label mean?
It is a maker's word, and NCCIH says it does not necessarily guarantee product quality or consistency. [9] Ask a pharmacist how to read a specific label.
What is the difference between an infusion and a decoction?
The EMA's herbal teas glossary describes an infusion as boiling water poured over the herb and a decoction as heating the herb in water and simmering. [7] This is a definition of terms, not instructions.
What does "traditional use" mean on a European herbal product?
In the EU it is a registration route for products with at least 30 years of use, including at least 15 years in the EU, where clinical trials are not required if safety data and plausible efficacy are shown. [11] It is not the same as a finding from a trial.
What does "preclinical" mean?
The FDA describes preclinical research as work done before testing a drug in people, to see whether it could cause serious harm. [14] We use "preclinical (cells or animals)" for findings that are not from human trials.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Regulator and tradition words
| Term | Plain meaning | Worth knowing |
|---|---|---|
| Traditional use registration (EU) | An EU route for herbal medicines. The EMA says it requires use for at least 30 years, including at least 15 years within the EU, and that no clinical tests and trials on safety and efficacy are required if sufficient safety data and plausible efficacy are shown. [11] | It rests on history of use. It is not proof from trials. |
| Well-established use (EU) | The EMA describes this route as scientific literature showing the active substances have been in well-established medicinal use in the EU for at least ten years, with recognised efficacy and an acceptable level of safety. [11] | Based on published literature, mostly bibliographic data. |
| HMPC and EU herbal monograph | The EMA's herbal committee (HMPC) establishes EU monographs covering the therapeutic uses and safe conditions of well-established and/or traditional use. [11] | The EMA says EU herbal monographs should not be confused with European Pharmacopoeia monographs, which cover quality requirements. [11] |
| US premarket review | NCCIH says the FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed. [2] | NCCIH adds that the FDA can act against adulterated or misbranded supplements only after the product is on the market. [9] |
See Herbal Monographs: Commission E, EMA and WHO and Traditional Use vs Research Evidence for more.
Safety words
| Term | Plain meaning | Worth knowing |
|---|---|---|
| Interaction | NCCIH says some herbs and medicines interact in harmful ways. [15] | NCCIH says St. John's wort can weaken the effects of many medicines. [15] See How Interactions Work. |
| Anticoagulant | A blood thinner, such as warfarin. NCCIH says ginkgo may increase the risk of bleeding in people taking anticoagulant drugs such as warfarin. [16] | NCCIH says garlic supplements may increase the risk of bleeding. [17] |
| Serotonin syndrome | MedlinePlus describes it as a potentially life-threatening reaction to certain medicines. [18] | NCCIH says St. John's wort taken with certain antidepressants or other drugs that affect serotonin may lead to increased serotonin-related side effects, which can be serious. [15] |
| Anaphylaxis | MedlinePlus: a serious allergic reaction that can begin very quickly and may be life-threatening. [19] | NCCIH says some people have allergic reactions to echinacea, which may be severe. [20] |
| Cross-reactivity (daisy family) | An allergy to one plant raising the chance of reacting to a relative. NCCIH says people allergic to ragweed, chrysanthemums, marigolds or daisies are more likely to react to chamomile. [21] | See Herbal Allergy and Cross-Reactivity. |
| Liver injury | NCCIH lists fatigue, nausea, poor appetite, dark urine or jaundice as liver damage symptoms to watch for with some curcumin products. [10] | NCCIH says liver injury has been reported, though uncommonly, with green tea products, mainly extracts in tablet or capsule form. [22] |
| Pyrrolizidine alkaloids (PAs) | NCCIH says the butterbur plant contains PAs, which can damage the liver and lungs and may cause cancer. [23] | NCCIH also notes rare liver injury with products reported to be PA-free. [23] |
| Glycyrrhizin | NCCIH says this component of licorice can cause serious effects such as irregular heartbeat and cardiac arrest, especially in large amounts or over the long term. [24] | Relevant to real licorice root, not every licorice-flavored product. |
| Thujone | NCCIH says some sage species, including common sage, contain thujone, which can be toxic if consumed in large amounts. [25] | |
| Cyanide-producing substances | NCCIH says raw or unripe elderberries and other elder parts such as leaves and stem contain these poisonous substances. [26] | See Elderberry. We give no preparation steps. |
| Anthraquinones (aloe latex) | NCCIH says non-decolorized aloe leaf extract has not had activated carbon treatment to remove toxic anthraquinone components. [27] | Gel, latex and whole-leaf extract are different products. |
| Adulteration | Product contents that differ from the label, or are contaminated. NCCIH says some commercial black cohosh products contained the wrong herb. [28] | NCCIH also says the FDA has found prescription drugs in products sold as supplements. [9] |
References
- National Library of Medicine, MedlinePlus. Herbal Medicine. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Dietary and Herbal Supplements, last updated February 2020. Read 2026-10-23.
- European Medicines Agency (EMA). Herbal substances (glossary). Read 2026-10-23.
- GBIF Secretariat. GBIF Backbone Taxonomy, species match for Rhamnus purshiana (API record). Read 2026-10-23.
- European Medicines Agency (EMA). Herbal preparations (glossary). Read 2026-10-23.
- European Medicines Agency (EMA). Herbal medicinal product (glossary). Read 2026-10-23.
- European Medicines Agency, Committee on Herbal Medicinal Products. Glossary on herbal teas, EMA/HMPC/5829/2010 Rev.1, 2010. Read 2026-10-23.
- European Medicines Agency, HMPC. European Union herbal monograph on Valeriana officinalis L., radix. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Using Dietary Supplements Wisely. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Turmeric. Read 2026-10-23.
- European Medicines Agency (EMA). Herbal medicinal products (regulatory overview). Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Placebo Effect. Read 2026-10-23.
- Cochrane. About Cochrane reviews. Read 2026-10-23.
- US Food and Drug Administration (FDA). Step 2: Preclinical Research. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). St. John’s Wort. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Ginkgo. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Garlic. Read 2026-10-23.
- National Library of Medicine, MedlinePlus Medical Encyclopedia. Serotonin syndrome. Review date 4/13/2026. Read 2026-10-23.
- National Library of Medicine, MedlinePlus. Anaphylaxis. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Echinacea. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Chamomile. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Green Tea. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Butterbur. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Licorice Root. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Sage. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Elderberry. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Aloe Vera. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Black Cohosh. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.