St. John’s wort – traditional uses and current research

St. John’s wort (Hypericum perforatum) is one of the best-known plants in European herbal medicine – with a tradition of use stretching back thousands of years and a wealth of scientific literature from recent decades. Find out about its botanical profile, its regulatory status in the EU as a traditional herbal medicinal product, its main active compounds, critical drug interactions, and why St John’s Wort should only be used following medical consultation.

St. John’s Wort (Latin: Hypericum perforatum) is a perennial herbaceous plant of the Hypericaceae family, occurring naturally throughout Europe, Western Asia, North Africa and – as an introduced species – in North America and Australia. It is a plant with a very rich history in European herbal medicine, dating back to the traditions of the ancient Greeks and Romans. Its characteristic yellow flowers with black dots on the petals (containing hypericin – one of the main active compounds) are recognisable to generations of European herbalists. St. John’s wort requires particular attention from consumers for two reasons: firstly, its regulatory status in the EU is unique – it is classified as a traditional herbal medicinal product (THMP), not as a food supplement. Secondly, St John’s wort has some of the most extensively documented drug interactions of any medicinal plant – capable of significantly reducing the efficacy of antiretroviral drugs, immunosuppressants, hormonal contraceptives and many others. For these reasons, this article is intended for educational purposes – it provides an accurate account of St John’s wort’s tradition and research status, but is not intended to encourage self-medication.

Botanical profile and history of use

St. John’s Wort is a herbaceous plant reaching 30–60 cm in height, flowering from June to August (hence the English name ‘St. John’s Wort’ – as it flowers around 24 June, the feast day of St John the Baptist). Distinctive botanical features:

Leaves – small, oval, with numerous translucent dots visible against the light. These ‘perforations’ (hence the Latin name ‘perforatum’) are glands containing essential oils.

Flowers – bright yellow, five-petalled, arranged in cymes. Black dots are visible on the petals – these are glands containing hypericin, St John’s wort’s most characteristic compound.

Aroma – slightly balsamic, pleasant, released particularly when the leaves are rubbed .

The tradition of using St John’s wort in European herbal medicine dates back to antiquity. Hippocrates, Dioscorides and Pliny the Elder described its uses in preparations intended for adults. In medieval Europe, St John’s wort was one of the cornerstones of the monastic herbal tradition – featured in the herbal manuals of Benedictine, Cistercian and Dominican abbeys. Hildegard of Bingen described it in her botanical works in the 12th century. In folk tradition, it was used in preparations intended for adults during periods of a demanding lifestyle.

In European folk culture, St John’s wort also held symbolic significance – it was hung in homes on 24 June as a ‘protective’ element of folk culture. St John’s wort oil (red oil macerated in the sun) was traditionally used externally – in preparations for minor skin irritations.

The regulatory status of St John’s wort in the European Union – an exception amongst herbs

This is an extremely important aspect of educating the informed consumer. St John’s wort has a regulatory status in the EU that is fundamentally different from that of typical herbal supplements (such as ashwagandha, turmeric and ginseng).

THMP (Traditional Herbal Medicinal Product) status - St. John’s wort is classified as a traditional herbal medicinal product, regulated by the European Medicines Agency (EMA). It has a monograph assessing its traditional clinical uses. This means that official St. John’s wort preparations are herbal medicines, not food supplements. In Polish pharmacies, St John’s wort is available as over-the-counter (OTC) medicines – under specific pharmaceutical names.

Practical implication: official, registered St. John’s wort preparations undergo European medicinal product registration procedures – with specified active ingredient content, controlled quality standards and indications approved by the EMA. This differs significantly from typical herbal supplements.

St. John’s wort dietary supplements in the EU – are very limited and subject to special supervision. Preparations containing standardised St. John’s wort extracts at doses typically used clinically (300–900 mg of hypericin-standardised extract) usually require registration as medicines. Supplements containing very low doses of powdered herb may be available, but their actual biological value is debatable.

Status in Poland: in Polish pharmacies, St John’s wort is sold primarily as an over-the-counter medicine – with a specific indication approved by the Office for Registration of Medicinal Products and a requirement to consult a pharmacist or doctor before use.

It is important for the informed consumer to understand that St John’s wort is not a ‘mood supplement’ – it is a medicinal plant with a potent pharmacological profile, the use of which should be supervised by a pharmacist or doctor, preferably in the form of officially registered pharmacy preparations.

The main active compounds in St John’s wort

St John’s wort contains a complex mixture of active compounds – from a phytochemical perspective, it is one of the more ‘complex’ European medicinal plants. Main groups of compounds:

Hypericin and pseudohypericin – an anthraquinone pigment that gives St John’s wort oil its red colour and is present in the black spots on the flowers and leaves. This was historically the first active compound identified in St John’s wort. Standardised extracts are often standardised for hypericin content (typically 0.3%).

Hyperforin and adhyperforin – phloroglucins present in higher concentrations in essential oils. Contemporary pharmacological research suggests that hyperforin is one of the main compounds responsible for the pharmacological effects of St John’s wort. Many standardised St John’s wort extracts are standardised for hyperforin content (typically 3–5%).

Flavonoids – quercetin, hyperoside, rutin, isoquercitrin, biapigenin. A rich group of polyphenols with antioxidant properties under laboratory conditions.

Essential oils – alpha-pinene, beta-pinene, caryophyllene, myrcene and many other terpenes.

Tannins, xanthones, phenolic acids – additional groups of biologically active compounds.

From the perspective of an informed consumer, two parameters are of paramount importance: standardisation for hypericin (typically 0.3 per cent) and/or standardisation for hyperforin (typically 3–5 per cent). Reputable official St John’s wort preparations specify both standardisations.

The state of clinical research – what we know

St. John’s wort is one of the most thoroughly researched medicinal plants in European phytotherapy. The number of clinical trials conducted over the last few decades runs into the hundreds – including randomised placebo-controlled trials, systematic meta-analyses and comparisons with conventional pharmacotherapy.

Research profile: research has focused primarily on mental health applications – mild and moderate mood disorders in adults. The results are generally moderately positive for mild forms, and mixed for moderate forms. The Cochrane Collaboration (a renowned international organisation specialising in medical meta-analyses) has published several systematic reviews of research on St John’s wort.

Regulatory status of these uses: official St. John’s wort preparations registered as traditional herbal medicinal products (THMPs) may contain specific indications approved by the EMA – however, these are therapeutic indications, not “health claims for a food supplement”. These two regulatory frameworks must be strictly distinguished.

An important caveat: the use of St John’s wort in any clinical context should be discussed with a doctor. St. John’s wort is not a substitute for psychiatric treatment – moderate and severe depression, anxiety disorders and adjustment disorders are conditions requiring professional diagnosis and individually tailored therapy. Self-medicating with St. John’s wort in the context of mental health problems may delay the start of appropriate treatment.

The most significant interactions between St John’s wort and medicines

This is probably the most important section of the entire article. St. John’s wort has some of the most extensively documented drug interactions of any medicinal plant used in European phytotherapy. An informed consumer should absolutely be aware of these interactions.

Mechanism of interaction: St. John’s wort induces the activity of cytochrome P450 liver enzymes (particularly CYP3A4, CYP1A2 and CYP2C9) and the activity of the P-glycoprotein transporter. Practical effect: medicines metabolised via these pathways are broken down more rapidly in the body – leading to a reduction in their blood levels and a potential loss of therapeutic efficacy.

The most serious interactions (where a loss of medicinal efficacy may have serious health consequences):

- Antiretroviral drugs – St. John’s wort may drastically reduce the levels of HIV protease inhibitors (ritonavir, indinavir, saquinavir) and non-nucleoside reverse transcriptase inhibitors. An absolute contraindication in people with HIV.

- Immunosuppressants (cyclosporine, tacrolimus, everolimus) – St. John’s wort may significantly reduce their blood levels, leading to transplant rejection. An absolute contraindication in people who have undergone organ transplants.

- Hormonal contraception – St. John’s wort reduces the effectiveness of both oral hormonal contraception and transdermal methods (patches). Using St. John’s wort whilst on hormonal contraception may lead to an unplanned pregnancy.

- Certain cancer drugs (imatinib, irinotecan, certain others) – St. John’s wort may significantly reduce their effectiveness.

- Warfarin and other anticoagulants – St. John’s wort may reduce warfarin levels, which may lead to ineffective anticoagulation and an increased risk of blood clots.

- Statins (atorvastatin, simvastatin and others) – the drug’s effectiveness may be reduced.

- Certain cardiac medicines (digoxin, certain antiarrhythmics) – possible interactions.

Pharmacodynamic interactions (increased risk of adverse effects):

- Antidepressants (SSRIs, SNRIs, MAOIs, tricyclic antidepressants) – combining St John’s wort with antidepressants may cause serotonin syndrome – a serious medical condition requiring hospital treatment. Absolute contraindication.

- Triptans (migraine medicines) – also carry a risk of serotonin syndrome.

- Certain painkillers (tramadol, certain opioids) – possible interactions.

Other effects: St. John’s wort causes photosensitivity of the skin – people using St. John’s wort preparations should avoid intense exposure to the sun and sunbeds. This effect has been known for centuries – hypericin, in the presence of UV radiation, can cause skin reactions.

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Alternative, safer approaches in a mindful routine

For those interested in supporting the nervous system, sleep quality or adapting to a demanding lifestyle, there are alternatives based on ingredients with EFSA-approved health claims (Category A) or on adaptogenic plants with a significantly lower interaction profile than St John’s wort.

Ingredients with approved EFSA health claims (scientific basis):

- Magnesium – “contributes to the normal functioning of the nervous system”; “contributes to normal psychological functions”; “contributes to the reduction of tiredness and fatigue”. The classic combination with vitamin B6 forms the foundation of a daily routine for people with demanding lifestyles.

- Vitamin B6 – “contributes to the normal functioning of the nervous system”; “contributes to normal psychological functions”.

- Vitamin B12 – “contributes to normal psychological functions”.

- Melatonin – “contributes to reducing the time taken to fall asleep” (at 1 mg before bedtime). The only EFSA-approved claim specifically relating to sleep.

Traditional adaptogens (Category B with research framework):

- Ashwagandha (Withania somnifera) – a traditional Ayurvedic adaptogen, intended for adults with demanding lifestyles. No EFSA-approved claims. A significantly lower risk of interactions than St John’s wort.

- Schisandra chinensis (Chinese magnolia vine) – a traditional adaptogen in Chinese medicine. No EFSA-approved claims. For more information, see the article Chinese magnolia vine (schisandra).

- Rhodiola rosea (golden root) – a classic Siberian adaptogen, traditionally found in preparations aimed at people leading lifestyles that are demanding in terms of climate and physical and mental exertion.

You can find the full range of natural adaptogenic plants in the Plants and Adaptogens category. Find out more about a mindful approach to supporting the nervous system in the articles B vitamins and supplements for energy and concentration.

[tip:Conscious support for the nervous system and sleep quality primarily involves good sleep hygiene, regular physical activity, a balanced diet, conscious stress management and maintaining social contacts. Supplementation can be a valuable addition – based on ingredients with approved EFSA claims (magnesium, B vitamins, melatonin to aid sleep) and traditional adaptogens with a better-documented safety profile than St John’s wort. Chronic mood, sleep or cognitive disorders require consultation with a GP or psychiatrist – not self-medication with supplements.]

Key situations in which St. John’s wort should NOT be used

The list is extensive and important. St. John’s wort should not be used by people:

- Taking antiretroviral medicines (for HIV)

- Who have undergone organ transplants (and are taking immunosuppressants)

- Using hormonal contraception

- Taking antidepressants (SSRIs, SNRIs, MAOIs, tricyclics)

- Taking anticoagulants (warfarin, NOACs)

- Taking anticancer drugs (chemotherapy, targeted therapy)

- Taking statins or other cardiac medications

- People with bipolar disorder (risk of triggering a manic episode)

- People with skin phototype I or II planning intense sun exposure (photosensitivity)

- During pregnancy and whilst breastfeeding

- Under the age of 18

- Before planned surgery (a minimum of 5–7 days’ withdrawal is recommended)

This is a long list – and that is why St John’s wort should only be used under the supervision of a pharmacist or doctor, with a full medical history covering current medications, medical conditions and life plans.

[warning: Absolute contraindications to the use of St John’s wort: use of antiretroviral drugs (HIV), immunosuppressants (following transplants), hormonal contraception (risk of unplanned pregnancy!), antidepressants (risk of serotonin syndrome!), anticoagulants, cancer drugs, statins, and certain cardiac medications. Any symptoms suggesting mood disorders, sleep disturbances or anxiety – such as depression, chronic sadness, anxiety, insomnia or adjustment disorders – require consultation with a GP or psychiatrist, rather than self-medication with St John’s wort or any other herb. A professional assessment allows for the selection of the best strategy – ranging from psychotherapy and lifestyle changes to tailored pharmacological treatment. St. John’s wort is a plant with a potent pharmacological profile – its use should be supervised by a pharmacist or doctor, preferably in the form of officially registered pharmacy preparations with a specific declaration of standardisation of active compounds.]

FAQ – frequently asked questions about St John’s wort

Is St John’s wort legal in Poland?

Yes – St John’s wort is legally available in Poland, but not as a typical dietary supplement. Official St. John’s wort preparations are registered as traditional herbal medicinal products (THMPs) – that is, over-the-counter (OTC) medicines sold in pharmacies. This means that purchasing them in a pharmacy usually involves a consultation with a pharmacist, who should ask about any medicines you are taking and any medical conditions you have before dispensing the product.

Can I drink St John’s wort tea every day?

St John’s wort tea in typical ‘kitchen’ quantities (1–2 tablespoons of dried herb per glass of water) contains significantly lower concentrations of active compounds than standardised preparations – and for most healthy adults, it should not cause clinically significant interactions. Nevertheless, if you are taking any long-term medication (particularly those on the list of absolute contraindications), even regular consumption of St John’s wort tea should be discussed with a pharmacist or doctor.

Can St. John’s wort be combined with other adaptogens?

Not recommended without medical consultation. Combining St. John’s wort with other adaptogens (ashwagandha, ginseng, rhodiola) or other herbs that affect the nervous system has not been well researched. St. John’s wort has such a potent pharmacological profile that combining it with other plants should only be done under the supervision of a professional.

Are there safer alternatives to St John’s wort

Yes. For those seeking support for the nervous system and sleep quality, there are alternatives with a better-documented safety profile: magnesium with vitamin B6 (EFSA-approved statements), melatonin (EFSA-approved statement on reducing the time taken to fall asleep), ashwagandha or schisandra (Category B with a research framework, but better interaction profiles than St John’s wort). For people experiencing chronic mood disorders or anxiety, the best first step is to consult a GP or psychiatrist – not to self-medicate with any medicinal plant.

Summary: St. John’s wort (Hypericum perforatum) is one of the best-known plants in European herbal medicine, with a tradition of use stretching back thousands of years and a wealth of research literature from recent decades. However, its regulatory status in the EU is unique – St John’s wort is classified as a traditional herbal medicinal product (THMP), not as a food supplement. In practice, this means that official St John’s wort preparations are herbal medicines sold in pharmacies, rather than supplements found in health food shops. The main active compounds in St John’s wort – hypericin and hyperforin – have a potent pharmacological profile. From the perspective of an informed consumer, the most significant feature of St John’s wort is its numerous, well-documented interactions with medicines: antiretrovirals, immunosuppressants, hormonal contraceptives, antidepressants, anticoagulants and many others. These interactions can lead to a loss of efficacy of the medicines or serious adverse effects – which makes St John’s wort a herb that should only be used under the supervision of a pharmacist or doctor. For those seeking support for the nervous system and sleep quality, there are safer alternatives based on ingredients with approved EFSA claims (magnesium, B vitamins, melatonin) or on adaptogenic plants with a significantly better safety profile (ashwagandha, schisandra, rhodiola). Any chronic mood, anxiety, sleep or cognitive disorders require consultation with a GP or psychiatrist – not self-medication with supplements.