Infusion, Decoction and Maceration: The Words and What Sources Mean by Them
What infusion, decoction, maceration, digestion and herbal tea mean in EU herbal medicine documents and in industry usage, and what research says about whether the method changes the cup.
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In EU herbal medicine documents, an infusion is boiling water poured over a herb and left to steep, a decoction is a herb heated in water and simmered, and a maceration is a herb soaked in water at room temperature. [1] The words describe how a water-based drink is made, not how strong it is, and not what it is for.
How the sources define the terms
The definitions below come from a 2016 HMPC template (EMA/HMPC/30603/2012). It points to a longer "Glossary of herbal teas" and to a European Pharmacopoeia monograph on herbal teas, which we did not read. [1]
| Term | Definition in the template |
|---|---|
| Herbal substance | Whole, fragmented or cut plants or plant parts, usually dried, defined by plant part and botanical name [1] |
| Herbal tea (plantae ad ptisanam) | One or more herbal substances meant for water-based oral preparations made by decoction, infusion or maceration; made immediately before use [1] |
| Tisane or ptisana | Also used for the drink made by those methods [1] |
| Herbal tea mixture | Herbal substances prepared in suitable sizes so they mix and do not separate [1] |
| Infusion | Boiling water poured on the herb, steeped for a defined time, usually 5 to 15 minutes if not specified [1] |
| Decoction | Cold water on the herb, heated to the boil and simmered, usually 15 to 30 minutes if not specified [1] |
| Maceration | Herb soaked in water at room temperature, usually about 30 minutes if not specified [1] |
| Digestion | Maceration with gentle heat above room temperature but not to boiling [1] |
| Drug extract ratio (DER) | Quantity of herb used divided by quantity of preparation obtained, written as a ratio [1] |
The DER is about extracts rather than teas; see extract ratios explained.
Two ways the word "infusion" is used
The template uses infusion for the process. The UK Tea and Infusions Association, an industry body, uses "herbal and fruit infusions" for a product category, and says herbals are infusions of leaves, roots, bark, seeds, flowers or fruits. [2] So "an infusion" can mean the method, the finished drink, or the dry product in the box. A "decoction" is used for the method and the drink. Read the context, and for exact meaning on a label see reading an herbal tea label.
Which plant parts, according to the template
The template says infusion is usually appropriate for leaves, flowers and delicate parts, and decoction or maceration for roots, rhizomes and barks. [1] It also says a decoction is generally not applicable to herbs with volatile active constituents. [1] For one example, the EU monograph for marshmallow root (Althaea officinalis L.) describes the tea as a macerate. [3]
What the sources do not say
- Not a tincture. Tinctures and extracts are separate preparations, sometimes added to a hot infusion in the template's optional wording. [1] See tincture vs extract.
- Not a strength ranking. The template says only that different preparations may have different actions and, in some circumstances, a different safety profile. [1]
- Not the same as traditional systems. The template says specific methods may apply for particular traditions or herbs. [1] We do not describe any tradition's methods here; see infusion vs decoction.
What research found about the method
| Question | What the source found | Evidence |
|---|---|---|
| Does extraction time change chamomile or St. John's wort water extracts? | Longer time changed rutin in St. John's wort; little effect on antioxidant activity in chamomile [4] | Laboratory chemistry only; no people studied |
| Does boiling change contamination? | Boiled decoctions had significantly fewer microbes than non-boiled in four Malaysian herbal medicines [5] | Laboratory; small sample of products |
| Human outcomes by method | Proper evidence not found: we searched PubMed for brewing, steeping and extraction studies of herbal teas and found no human trial comparing methods | None |
Frequently asked questions
What is the difference between an infusion and a decoction?
In the EU template, an infusion pours boiling water on the herb and steeps it, while a decoction starts with cold water, heats to the boil and simmers. [1]
What is a maceration?
Soaking the herb in water at room temperature, usually about 30 minutes if not specified; gentle warming short of boiling is called digestion. [1]
Is a tisane the same as an infusion?
The EU template uses "tisanes" for the drink made by infusion, decoction or maceration, so they overlap. [1]
Does the method change how well a herbal tea works?
Proper evidence not found for human outcomes. The EU says different preparations may have different actions. [1]
Where can I find the full glossary?
The template names the EMA's Glossary of herbal teas; we did not read it, so we cite only the template. [1]
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
The EU says the method can matter for safety. [1] We do not give a method for any plant that can be toxic. If a plant is known to be harmful, the answer is not a better method. See Herbal tea and extract safety. Ask a pharmacist or clinician if you take medicines or are pregnant or breastfeeding. For general cautions see medication interactions.
References
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Patient Leaflet template concerning advice on the preparation of herbal teas as (traditional) herbal medicinal products by end-users, EMA/HMPC/30603/2012, adopted 20 September 2016. Read 2026-10-23.
- UK Tea and Infusions Association (industry body). About Herbal Infusions. Read 2026-10-23.
- European Medicines Agency, HMPC. European Union herbal monograph on Althaea officinalis L., radix, EMA/HMPC/436679/2015, 12 July 2016. Read 2026-10-23.
- Sentkowska A, Biesaga M, Pyrzynska K. Effects of brewing process on phenolic compounds and antioxidant activity of herbs. Food Sci Biotechnol. 2016;25(4):965-970. PubMed 30263361. Read 2026-10-23.
- Ting A, Chow Y, Tan W. Microbial and heavy metal contamination in commonly consumed traditional Chinese herbal medicines. J Tradit Chin Med. 2013;33(1):119-124. PubMed 23596824. Read 2026-10-23.