St. John’s Wort (Hypericum perforatum)

With its bright yellow, five-petaled flowers a familiar roadside sight in early summer, St. John’s wort is said to be named because it flowers on June 24th — St. John’s Day — observing the birth of St. John the Baptist. It is a well-known and sometimes controversial herb whose properties were first recorded by Hippocrates in ancient Greece. In his chapter on the herb in the 2010 edition of the Encyclopedia of Dietary Supplements, FDA psychopharmacologist Jerry Cott, PhD, wrote that St. John’s wort is “one of the best known and well researched of the western herbals.”

The botanical name, Hypericum perforatum, reflects the traditional story of the plant’s common name. Hypericum is derived from the Greek words hyper (above) and eikon (picture), in reference to the plant’s traditional use in warding off evil by hanging plants over a religious icon in the house during St. John’s day. Perforatum refers to the presence of small oil glands in the leaves that look like small pinpricks, giving them a perforated look when the leaf is held up against the light.

St. John’s wort is often considered a weed, a hardy perennial that can be found growing wild on roadsides, fields and hillsides. In fact, it is considered a noxious weed in nine states in the West! It is indigenous to all of Europe, western Asia and northern Africa.

The flowers are the main part of the plant that is used, and they are best picked just as the buds begin to open. The telltale sign that the buds are ready to pick is the red stain that will be on your fingers. St. John’s wort propagates itself by casting its seeds, so make sure to leave some flowers to go to seed to ensure continued availability.

A Medicinal Powerhouse

St. John’s wort has a number of medicinal uses. As a nervine, it is helpful for anxiety, stress, mild depression, nerve damage and Seasonal Affective Disorder (SAD). St. John’s wort also has anti-bacterial, antiviral and anti-inflammatory properties, and when used internally can be helpful with infections. It also has sedative and pain-relieving effects. Used externally, St. John’s wort soothes and heals bruises, sprains, burns and promotes tissue repair and speeds recovery.

Sixteenth century herbalist Nicholas Culpepper recommended an oil-based St. John’s wort ointment for swellings and burns. Europeans prepared a tincture of flowers and leaves as an antibiotic and to relieve inflammation. Cherokee Indians used the mucilage from the leaves as an ointment for bruises and burns and introduced the plant to early colonists.

Every household should have a bottle of St. John’s wort oil in their medicine cabinet; making St. John’s wort oil is a summer ritual for the herbalist. My favorite method is:

Pick buds of St. John’s wort when the flower is just ready to open. Place buds in a clean glass jar and cover with olive oil, leaving an inch of oil at the top. I do this over several weeks, each day picking the new buds on the plants, placing them in the jar and adding more olive oil when needed. Place in direct sunlight and let infuse for 2-3 weeks. The oil will become a deep, rich, clear red. Strain and bottle. To use: Spread oil over burn, bruises or cuts, add to skin and burn balms as the oil component. Some herbalists also use the plant leaf and open flowers, and some chop the buds and flowers before infusing. I find the buds give the most oil content.

St. John’s wort is more commonly known, however, for its use with mild depression. St. John’s wort extracts were more effective than a placebo in the treatment of mild to moderate depression in multiple controlled trials, although no more effective than a placebo for major depression. In countries such as Germany, St. John’s wort is commonly prescribed for mild to moderate depression, especially in children and adolescents. In Germany, St. John’s wort is the leading antidepressant prescribed by doctors.

Even with all the studies done, nobody knows for certain exactly how St. John’s wort works in regards to depression but there are several antidepressant agents in the plant, the prime phytochemicals being hypericin and hyperforin. Hypericin increases the metabolism of serotonin and melatonin. Hyperforin alters brain chemistry and slows the uptake of three important neurotransmitters: dopamine, serotonin and noradrenaline. These neurotransmitters are what regulate mood and emotions. Dopamine is a “feel good” brain chemical, serotonin is mood enhancing, and noradrenalin is responsible for feelings of alertness and energy. By allowing these neurotransmitters to circulate longer in the body the good feeling resulting from them is enhanced.

St. John’s wort also improves the signal produced by serotonin after it binds to its receptor site on brain cells and the feeling of enhanced mood and wellbeing is transferred more effectively from one brain cell to the next. This mechanism of action on all three main neurotransmitters is unique, and most researchers believe that the effects of St. John’s Wort are due to a synergistic interaction between several of its many compounds, as is the case with many herbs.

Comparing Side Effects

There have been many studies done comparing St. John’s wort with antidepressant drugs and also with their respective side effects. SSRIs (selective serotonin reuptake inhibitors) such as fluoxetine and sertraline are successful in improving the symptoms of depression in nearly 60% of depression sufferers. They, together with the older tricyclic antidepressants, however, have many side effects, including nausea, headaches, anxiety and nervousness, insomnia, drowsiness, diarrhea, dry mouth, loss of appetite, sweating, tremors and sexual dysfunction. The sexual problems are the main reasons why people stop taking these drugs.

The most common adverse effects from St. John’s wort reported are gastrointestinal symptoms, dizziness, confusion, tiredness and sedation. St. Johns wort can cause photosensitivity in some people.

A thorough read of the package insert if using prescription antidepressants is helpful so one can know the side effects and then make an informed decision as to whether they want to use it or discuss with their primary health care provider trying a natural alternative, such as St. John’s wort. Using St. John’s wort for depression does take time, and it is recommended that 4-8 weeks of use be allowed for results to show.

There has also been controversy and conflicting research on the use of St. John’s wort with other prescription medications. The Center for Science in the Public Interest (CSPI) asserts that “St. John’s wort and many commonly prescribed drugs simply don’t mix,” but some experts on St. John’s wort herb-drug interactions say the group’s science is inadequate and inaccurate.

Some of the common precautions given with St. John’s wort include:

  • don’t take it with a prescription antidepressant
  • it can also adversely affect hormonal contraceptives (especially those containing acitretin)
  • St. Johns wort use should be stopped five days before surgery using anesthetics as it has been associated with complications such as hypotension and delayed emergence from anesthesia
  • St. Johns wort should not be used with anticoagulants, antidiabetic agents, or barbiturates

Digging deeper, it appears the amount of hyperforin consumed makes a difference in any interactions. St. John’s wort products with low or no hyperforin seem to have no contraindications with prescription drugs. Herbalgram, the publication of the American Botanical Council, has an excellent article on this topic titled “Herbal Experts Say CSPI Petition for St. John’s Wort Warning Inaccurate” (Volume 8, Number 12, December 2011) for further reading.

Include St. John’s wort in your herbal medicine cabinet and enjoy the many uses of this incredible herb.


  • Medicinal Herbs, A Beginners Guide, Rosemary Gladstar. Storey Publishing, 2012
  • The Herb Companion Special Reference Issue, Guide to Healing Herbs, Anita B. Stone, Ogden Publications
  • The Herbal Medicine Maker’s Handbook, A Home Journal, James Green, Crossing Press, 2000
  • PDR for Herbal Medicines, Third Edition, Thompson PDR, 2004
  • “Herbal Experts Say CSPI Petition for St. John’s Wort Warning Inaccurate,” HerbalEGram: Volume 8, Number 12, December 2011

Linda Russell is an herbalist, educator and plant lover.

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The Joys of Plant and Natural Medicine
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