Forms & Preparations
Teas, tinctures, extracts, capsules and powders are different products. See why a study of one form does not carry over to another, with examples from NCCIH and EMA.
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.
The same plant can reach you as a tea, a liquid extract, a tablet, a capsule or a powder. These are not interchangeable. What a study found for one form does not automatically apply to another, and the risks can differ too. This page is the overview of forms. Each form has its own page, linked below. It gives no recipes and no amounts for a person to use.
If you take prescription medicines, are pregnant or breastfeeding, have liver or kidney disease, or have surgery planned, ask a pharmacist or clinician before choosing any herbal product. Start with how herbs and medicines interact.
What the words mean
The European Medicines Agency (EMA, the European Union's medicines regulator) uses two terms that make the rest easy to follow. An herbal substance is the plant material itself, usually dried, "precisely defined by the plant part used and the botanical name". [1] An herbal preparation is what you get after a treatment such as extraction, distillation or concentration. EMA's list of preparations includes "comminuted or powdered herbal substances, tinctures, extracts, essential oils, expressed juices". [2]
US sources describe the same range for products sold to consumers. MedlinePlus says herbal medicines are sold "as tablets, capsules, powders, teas, extracts, and fresh or dried plants". [3] NCCIH, part of the US National Institutes of Health, adds that supplements in stores "may differ in important ways from products tested in studies". [4]
The forms at a glance
| Form | What it is (plain description) | Where to read more |
|---|---|---|
| Tea, infusion, decoction | Plant material steeped or simmered in water and drunk | More about Tea, infusion, decoction → |
| Tincture, fluid extract, glycerite | Liquid extracts made with a solvent such as alcohol | More about Tincture, fluid extract, glycerite → |
| Capsule, tablet, powder | Dried plant or dried extract in a solid form | More about Capsule, tablet, powder → |
| Standardized extract | An extract measured for one or more marker compounds | More about Standardized extract → |
| Syrups, lozenges, gummies | Sweetened or flavored products | More about Syrups, lozenges, gummies → |
Why the form matters: examples from NCCIH
These examples show how a form changes the evidence or the risk. Each describes one product type only.
| Plant | Form difference documented | Source |
|---|---|---|
| Green tea (Camellia sinensis, leaf) | NCCIH reports no safety concerns for green tea as a drink in adults. Liver injury, though uncommon, has been reported "primarily" with extracts in tablet or capsule form. Most cholesterol studies tested extract supplements, not the drink. | [5] |
| Turmeric (Curcuma longa, rhizome) | NCCIH says highly bioavailable curcumin formulations "may harm your liver", and that curcumin products vary in how much curcumin they contain. Many also contain piperine from black pepper. | [6] |
| Elderberry (Sambucus nigra) | Raw or unripe berries and other parts of the tree (leaves, stem) contain poisonous cyanide-producing substances. This is a reason to avoid unprocessed plant parts, not a reason to experiment. | [7] |
| Echinacea (Echinacea species) | NCCIH-sponsored research suggests the activity of extracts is influenced by soil conditions that affect the plant's bacterial community. Species, plant part and growing conditions can all differ between products. | [8] |
| Milk thistle (Silybum marianum, seed extract) | Extracts are described by silymarin content. Some products were found to contain silymarin amounts "substantially different" from the label. | [9] |
| Chamomile (Matricaria chamomilla, flower) | Some studies tested chamomile plus other herbs, so chamomile's own role is hard to judge. Certain herb combinations including chamomile may help children's diarrhea and infant colic, but chamomile alone has not been shown to. | [10] |
For the full profiles, see turmeric, green tea, elderberry, echinacea and milk thistle.
Evidence and the form: what we can and cannot say
Research results are tied to what was tested: the plant part, the preparation, the population and the outcome. A trial of a standardized capsule does not show that the tea works. A safety signal for an extract does not prove the tea is unsafe, and a tea's long use does not prove an extract is safe. Where the sources we read compare forms head to head, we say so on the herb's own page. For most herbs, Proper evidence not found for a direct comparison between a tea and an extract: we looked in the NCCIH herb pages and the EMA monograph we read, and they do not make that comparison.
Frequently asked questions
Is a tea weaker than a capsule?
Not necessarily, and not in a way the sources we read measure. The two are different products, and the amount of plant compounds in each depends on the plant, the part used, how it was prepared and the product. A regulator's tea glossary says different preparations "may exert different actions" and may have "a different safety profile". [11]
Can I use a study of an extract to judge a tea?
No. For green tea, NCCIH notes that most cholesterol studies tested extract supplements rather than the drink. [5] The result belongs to the form that was tested.
Does "natural" mean a form is safe?
No. MedlinePlus says herbs such as comfrey and ephedra can cause serious harm and that some interact with medicines. [3] See why natural does not mean safe.
Which form should I choose?
There is no universal best form, and we do not rank products. A pharmacist or clinician who knows your medicines and health conditions can help you decide.
How do I know what is in a product?
Read the label for the scientific name and plant part, and see reading supplement labels. Note that NCCIH warns "standardized" does not necessarily guarantee quality or consistency. [4]
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.
Safety that applies to every form
- Medicines: herbs can interact with prescription and over-the-counter medicines. See herb-drug interactions.
- Surgery: NCCIH notes that "certain dietary supplements may increase the risk of bleeding or affect your response to anesthesia". Tell the surgical team about every product. [4] See supplements before surgery.
- Pregnancy, breastfeeding and children: see pregnancy and breastfeeding and children and teens.
- Testing: MedlinePlus notes herbal medicines do not have to go through the testing that drugs do. [3] See product quality and contamination.
Essential oils are a separate category with their own rules. See Essential Oils & Aromatherapy.
References
- European Medicines Agency. Herbal substances (glossary). Read 2026-10-23.
- European Medicines Agency. Herbal preparations (glossary). Read 2026-10-23.
- MedlinePlus (US National Library of Medicine). Herbal Medicine. Read 2026-10-23.
- NCCIH (US). Using Dietary Supplements Wisely. Read 2026-10-23.
- NCCIH (US). Green Tea. Read 2026-10-23.
- NCCIH (US). Turmeric. Read 2026-10-23.
- NCCIH (US). Elderberry. Read 2026-10-23.
- NCCIH (US). Echinacea. Read 2026-10-23.
- NCCIH (US). Milk Thistle. Read 2026-10-23.
- NCCIH (US). Chamomile. 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.