Hypericum perforatum

Other names: St John's wort

Yellow flowers; translucent dots in the leaves.

Golden flowers and opposite leaves.

Family: Hypericaceae
Plant type: Perennial herb
Safety level (indicative): Caution

What the safety levels mean (expand legend)

Generally recognised as safe. Often a common herb with reasonable harvest and use; still read the specific warnings on the card.
Information. Primarily informational — details in the text and warnings below matter most.
Caution. Needs extra care (dose, duration, sensitive groups, interactions).
Risky. Significant risks — verify sources, contraindications and professional guidance.
Not for home experimentation. Not suitable to experiment with at home without knowledge and certainty.
High risk for internal use. Particular risk with internal use (e.g. alkaloids); avoid prolonged or irresponsible dosing.
Not specified. Level not filled in yet — rely on individual warnings and links below.

Třezalka tečkovaná — habitus rostliny (Wikimedia Commons). — Fotografie na Wikimedia Commons (CC BY-SA 4.0).
Plant habit

Safety — read before use

For this herb it is important to check warnings, mix-ups and cautions. Start with the Safety section.

Quick overview

A practical summary; details are in the sections below.

Safety grade: Caution·details
Scientific sources on the card: Yes — sources are listed with claims·Science section
When and what to harvest: Flower — June–August
Full harvest section
Processing methods: Herbal infusion (tea), Herbal oil, Honey macerate, Capsules
All methods and recipes on the card
Topics and symptoms: Mood swings, Sadness and melancholy, Topic…
Topics section · Symptoms overview

Identification and mix-ups

Hold leaves to the light to see translucent dots.

Possible mix-ups and risks

Interactions and photosensitivity—check trusted references.

Similar herbs

Melissa officinalis
Často spolu v diskuzi o „klidu“ a bylinných čajích — třezalka má zvláštní témata interakcí a slunce.

Topics and symptoms

More topics are in the symptoms and topics overview.

Mood swings
Traditional· Traditional / cultural framing
Sadness and melancholy
Traditional· Traditional / cultural framing
Topic
Scientific· Preliminary or weaker scientific findings
Topic
Scientific· Preliminary or weaker scientific findingsTraditional· Traditional / cultural framing
Trauma - gentle symbolic support
Traditional· Traditional / cultural framing

Drug interactions and photosensitivity

Information on the card — not a substitute for professional medical care or individual assessment.

Drug interactions

Literature reports major interactions with many drugs (e.g. some anticoagulants, antidepressants, antivirals, immunosuppressants). If you take medication, consult a clinician and authoritative sources.

Photosensitivity

Sensitive people may develop skin photosensitivity after contact or use—sun avoidance may be appropriate depending on sources and individual tolerance.

Geographic occurrence

Czechia
Common (expected wild occurrence in the region)
Austria
Common (expected wild occurrence in the region)
Germany
Common (expected wild occurrence in the region)
Hungary
Common (expected wild occurrence in the region)
Poland
Common (expected wild occurrence in the region)
Slovakia
Common (expected wild occurrence in the region)
France
Common (expected wild occurrence in the region)
Japan
Occasional (garden, cultivation, or fringe of the range)
Canada
Occasional (garden, cultivation, or fringe of the range)
Australia
Occasional (garden, cultivation, or fringe of the range)

Harvest

FlowerJune–August
léto
Region: Czechia
Notes: Harvest note (full translation pending): Kvetni vrcholy — pozor na fotosenzitivitu.

Storage

Drying(Leaf)
Sušený rostlinný materiál uchovávej v uzavřené nádobě.
Light:
Mimo přímé UV.
Moisture:
Nízká relativní vlhkost.

Processing methods on this herb card

Herbal infusion (tea)(Flower)Suitability: High suitability
Infusion or brief extraction in hot water; usually without long boiling.
Full method description (from the catalogue)
In the narrow sense, “tea” often means an infusion: you pour water just off the boil over the dried plant matter and let it steep for a few minutes. Temperature, steep time, and the herb-to-water ratio change both flavour and what dissolves into the liquid.
Compared with a decoction, heat exposure is shorter and gentler; tender leaves and flowers are often better as an infusion than with prolonged simmering. For each herb, always follow the plant card for suitable plant part, preparation, and safety notes — general rules never replace species-level judgement.
Traditional context for this method: yes·Scientific context for this method: no
Procedure (recipe)
St John's wort flower tea
About 12 min · Difficulty: Beginner
Extraction parameters (rough guide): 250 ml water · 90–100 °C · 8–12 min steep
1. Use dried flowering tops in dry weather (if fresh, allow brief wilting first).
2. Use 1–2 teaspoons of dried herb per cup (adjust proportion if using fresh material).
3. Pour boiling water, cover, steep 8–12 minutes, then strain.
Possible drug interactions and photosensitivity — see the herb card and professional sources.
Why this way (extraction / behaviour of constituents)
EMA documentation on St John's wort herb highlights interactions and photosensitivity for approved products; these themes may still matter for weaker home flower infusions, but intensity is not the same. Shorter steeping shifts the extract profile compared to a long decoction.
What is typically released
Směs polárních a lipofilnějších frakcí — variabilní podle suroviny.
Solvent / water
Voda; mimo přímé slunce při louhování.
After preparation
Pij čerstvě připravené; skladuj krátce v chladu.
Extra literature for the recipe
- EMA HMPC — Hypericum perforatum, herba (rev. 1)Květný čaj doma ≠ „herba“ v dokumentu; interakce ověř u lékaře.
Herbal oil(Flower)Suitability: High suitability
Macerating herbs in a vegetable oil (cold or with gentle heat).
Full method description (from the catalogue)
Herbal oil is made by steeping dried or fresh material in oil (e.g. olive, sunflower) over time, sometimes with gentle warming. The result is not steam-distilled essential oil — it is a different extract type and usage (often topical or culinary per recipe).
Temperature, light, and material moisture affect shelf life; rancid oil must be discarded.
Traditional context for this method: yes·Scientific context for this method: no
Procedure (recipe)
Red St John's wort flower oil
About 40 min · Difficulty: Intermediate
1. Fill a jar with flowers and cover with good plant oil (olive or sunflower) so they stay submerged.
2. Macerate 4–6 weeks in direct sun or on a warm windowsill, shaking daily — the oil turns red.
3. Strain through cloth, store cool and dark; use on intact skin only.
Photosensitivity and drug interactions — see the herb card; avoid sun after application.
Why this way (extraction / behaviour of constituents)
Traditional red St John's wort oil depends on light-driven changes in dissolved pigments and an oil-soluble plant fraction; photosensitisation risk can remain relevant depending on plant part, sun exposure during maceration, and skin status. External use on intact skin only; avoid sun after application and check drug interactions on the herb card.
What is typically released
orientační domácí extrakce — profil závisí na teplotě, čase řezu a poměrech
Solvent / water
mediální složení (voda, alkohol, olej, med…) viz jednotlivé kroky
After preparation
po přípravě uchovávej hygienicky a podle typu výrobku (chlad, světlo, alkohol)
Extra literature for the recipe
- Vyhledávání studií (PubMed apod.)Konkrétní vědecká tvrzení ověř na kartě byliny a v primární literatuře.
Honey macerate(Flower)Suitability: Medium suitability
Macerating plant material in honey (a honey conserve).
Full method description (from the catalogue)
Honey as a maceration medium creates a viscous mixture with its own biochemistry: water activity, acidity, and enzymes influence shelf life and flavour. Traditionally it is used with delicate flowers or herbs when you want aroma bound into honey.
Infant botulism guidance for honey and honey safety in general sit outside a single herb page; maceration time, ratios, and storage must follow a vetted recipe and source, not this general overview alone.
Traditional context for this method: yes·Scientific context for this method: no
Procedure (recipe)
St John's wort flower honey
About 30 min · Difficulty: Beginner
1. Fill a jar about one third with dried flowers and cover with honey.
2. Macerate 2–3 weeks away from direct sunlight, then strain.
3. Mind drug interactions and photosensitivity — see the herb card.
Maceration takes weeks; do not combine with medicines without checking interactions.
Why this way (extraction / behaviour of constituents)
Hyperforin and hypericin have a complex relationship with solvents; honey as a mixture of sugars and water may only release part of the lipophilic and polar fractions from flowers. Pharmacokinetic interactions known from St John's wort products may still matter for food-like preparations—check any prescription combinations.
What is typically released
Směs polárních a lipofilnějších složek v medu — variabilní profil.
Solvent / water
Med; macerace 2–3 týdny mimo přímé slunce.
After preparation
Po scedění chladně; při změně barvy sleduj stabilitu.
Extra literature for the recipe
- Clinical relevance of St. John's wort drug interactions revisitedInterakce s léky — paralela k opatrnosti u medu s květy.
- St John's wort for major depression (Cochrane systematic review)Kontext účinnosti u deprese u klinických preparátů; domácí med není ekvivalent.
Capsules(Flower)Suitability: Medium suitability
Filling capsules with dried herb or powder; home and industrial variants.
Full method description (from the catalogue)
Capsules allow precise dosing and mask bitter tastes. Home fillers exist, but hygiene, blend uniformity, and storage are harder than with tea.
Follow supplement legislation where it applies.
Traditional context for this method: no·Scientific context for this method: yes
Procedure (recipe)
St John’s wort capsules (orientation)
About 10 min · Difficulty: Advanced
1. Market capsules use standardised St John’s wort extract — home-filled dry herb has no controlled hypericin level.
2. Extracts interact with many drugs — inform your doctor and read supplement leaflets.
Photosensitivity and drug interactions — see the herb card.
Why this way (extraction / behaviour of constituents)
Home preparation following this recipe is mainly educational and cultural; it should not be assumed to match the extractive or safety profile of registered medicines or standardized extracts. Check specific effects, drug interactions, and contraindications on the herb card and with your clinician if you use prescription drugs.
What is typically released
orientační domácí extrakce — profil závisí na teplotě, čase řezu a poměrech
Solvent / water
mediální složení (voda, alkohol, olej, med…) viz jednotlivé kroky
After preparation
po přípravě uchovávej hygienicky a podle typu výrobku (chlad, světlo, alkohol)
Extra literature for the recipe
- Vyhledávání studií (PubMed apod.)Konkrétní vědecká tvrzení ověř na kartě byliny a v primární literatuře.

Traditional / spiritual use

Kept separate from science — entries are cultural or symbolic, not medical advice.

Related guides in the library

St John's wort, midsummer, and a yellow field
General
Traditional useFolk useHerbal lore
St John's wort links in many countries to midsummer feasts and a yellow field in the longest days. Calendar and open-land symbolism sit apart from modern drug interaction and photosensitivity warnings on the card.
Form:
čaj, olejové maceráty v lidové praxi
Claim strength:
Tradition
Source note:
Calendar and Christian-cultural layers in Europe; not a spiritual dosing guide.

Scientific notes

Each claim lists a study type and a source (URL or DOI) where available. Dose notes from the literature are informational only.

How to read evidence strength and study type labels

Labels summarise how the catalogue entry is tagged — they are not a medical verdict on efficacy. For every row, read the summary, limitations and source link.

Evidence strength

Evidence level not specified: The author did not grade the record; judge from the summary, limitations and source link.
Narrative / orientational literature: Descriptive or expert literature without controlled group comparison — context rather than proof of effect.
Weak evidence: Study or conclusion with major methodological limits; treat only as a pointer for further reading.
Preliminary findings: First or smaller studies — interesting direction, not the final word on efficacy or safety.
Moderate strength of evidence: Moderate strength by study design; sample and context limits still apply.
Stronger evidence: Stronger design or consistency of results within the study’s stated limits.
Review article: A review summarises multiple sources; quality depends on review method and field.

Study type

Narrative / expert text: Expert text or overview without a classical study design.
In vitro study: Cell culture or test-tube experiment — does not show an effect in the body.
Animal study: Animal model — transfer to humans is not automatic.
Observational study: Observing groups without random treatment assignment; confounding is possible.
Clinical trial: Human clinical trial; sample size and control group matter.
Randomised controlled trial: Randomised controlled trials are among the stronger designs when well conducted.
Review study: A review aggregates multiple papers — quality depends on selection rules.
Systematic review: Systematic review with explicit search and selection methodology.
Meta-analysis: Statistical pooling of studies; outcome depends on input data and heterogeneity.
Regulatory assessment / monograph (EMA, WHO…): Regulatory body summary for a herbal product — different context from a single RCT; often about products, not home tea.
Expert monograph (herbal preparations): Structured literature summary for a plant or drug — quality depends on author and edition year.

Hypericum perforatum extracts (standardised) show antidepressant activity in several meta-analyses; photosensitivity and extensive CYP450 interactions are well established.
Review articleSystematic reviewYear: 2008
Limitations: Not comparable to casual garden tea; induction of drug metabolism can lower levels of oral contraceptives, immunosuppressants, and others; UV skin reactions documented.
Linde K, Berner MM, Kriston L — Cochrane Database of Systematic Reviews
St John's wort for major depression (Cochrane systematic review)
DOI: 10.1002/14651858.CD000448.pub3
Evidence summary (full translation pending): Prehled klinickych interakci shrnuje, ze trezalka indukuje CYP3A4 a P-glykoprotein (zavisle na hyperforinu) a muze snizovat hladiny rady leku (napr. imunosupresiva, antikoagulancia, antikoncepce); stupen indukce koreluje s obsahem hyperforinu v preparatu.
Moderate strength of evidenceReview studyYear: 2020
Limitations: Limitations (translation pending): Ne vsechny komercni pripravky maji stejny obsah hyperforinu; open-access plny text tez PMC7056460; souhrn nenahrazuje individualni posouzeni s lekarem nebo lekarnikem.
Meyer zu Schwabedissen HE — British Journal of Pharmacology
Clinical relevance of St. John's wort drug interactions revisited
DOI: 10.1111/bph.14936
Evidence summary (full translation pending): EMA HMPC pro nat trezalky popisuje schvalene pripravky a bezpecnostni ramec vcetne interakci; horky nalev z kvetu neni totez co standardizovany extrakt.
Review articleRegulatory assessment / monograph (EMA, WHO…)Year: 2022
Preparation form in the study: infusion
Active compound / focus: hypericin, hyperforin, flavonoidy (dle dokumentu)
Limitations: Limitations (translation pending): Kvetny caj v kuchyni se muze lisit od „herba“ v monografii; interakce s leky zustavaji relevantni.
Dose note (from literature): Dosage notes (translation pending): Neuzivej soucasne s leky bez overeni u lekare.
EMA Committee on Herbal Medicinal Products (HMPC) — European Medicines Agency
EMA: Final assessment report on Hypericum perforatum L., herba (revision 1)

Images

The main photo is in the card header. More images will appear here when available.

Safety

What the warning types mean

The type on each warning helps group themes — it does not replace the separate severity badge.

Internal use: Risks from swallowing, extracts, duration of use or concentration for internal use.
Interactions / medicines: Possible effect on medicines or concurrent treatment — check sources and a professional.
Raw plant parts: Raw, unripe or poorly prepared plant parts can be dangerous.
Toxins and regulation: Toxic constituents or regulated compounds (e.g. in distillates).
Contact with the plant: Skin or mucosa irritation from contact with fresh plant or sap.
Allergy: Allergic reactions, often linked to family sensitisation.
Harvesting and contamination: Contamination, species mix-ups or harvesting from unsuitable places.

Safety information (full translation pending)Moderate severityInteractions / medicines
This warning is being translated to English. Czech editor text: Fotosenzitivita / leky Trezalka muze ovlivnit ucinek nekterych leku a citlivost ke slunci.