St. John's Wort (Hypericum perforatum)

Dried aerial parts of Hypericum perforatum, St. John's Wort, the bright yellow-flowered European herb best known for its traditional and modern use in mood support. The plant gets its English name from its peak flowering around the feast day of Saint John the Baptist (June 24), and "perforatum" from the tiny translucent glands on the leaves that look like perforations when held to the light.

Key Facts

Botanical name

Hypericum perforatum

Family

Hypericaceae

Common names

St. John's Wort, Klamath Weed, Goatweed, Tipton's Weed

Native region

Europe and parts of Asia; widely naturalized globally

Studied compounds

Hypericin, hyperforin, flavonoids

Modern use

One of the most-studied herbs for mood support in modern pharmacology

What is St. John's Wort?

St. John's Wort is a perennial herb with five-petaled bright yellow flowers and small oval leaves marked with tiny translucent glands. The plant has a long traditional use in European herbalism dating to ancient Greek and Roman texts. Modern research has produced extensive clinical literature on St. John's Wort for mild to moderate mood support; the herb is approved as a prescription antidepressant in Germany and other parts of Europe.

Important: Drug Interactions

St. John's Wort has significant interactions with many medications. The compound hyperforin induces cytochrome P450 liver enzymes, which can reduce the effectiveness of: birth control pills, blood thinners (warfarin), HIV medications, transplant rejection medications, chemotherapy drugs, certain heart medications, and many others. Do not combine St. John's Wort with prescription medications without consulting a healthcare provider and pharmacist first. Also, do not combine with SSRIs or other antidepressants (risk of serotonin syndrome).

How to Use St. John's Wort

For tea: steep 1-2 teaspoons of dried herb per 8 oz cup in hot water for 10 minutes; strain. For tincture: a base for measured dosing. For infused oil (traditional topical use): cover dried flowers with olive oil in a jar, set in sunlight for 3-6 weeks (the oil turns red from hypericin extraction), strain. The red oil is a traditional preparation for skin and topical application.

Frequently Asked Questions

What is St. John's Wort used for?
Most commonly for mood support; also topically as an infused oil for skin applications.

Does St. John's Wort interact with medications?
Yes; significant interactions with many prescription medications including birth control, blood thinners, antidepressants, HIV medications, and many others. Consult a healthcare provider before combining.

Why is the oil red?
Hypericin extraction colors the infused oil deep red.

Why is it called "St. John's Wort"?
The plant typically peaks in flowering around June 24, the feast day of Saint John the Baptist.

What's the difference between hypericin and hyperforin?
Both are bioactive compounds. Hyperforin is the primary compound associated with mood effects and drug interactions; hypericin gives the red color to the oil.

Can St. John's Wort cause photosensitivity?
Yes; at high doses, the hypericin content can increase skin sensitivity to sunlight.

This product has not been approved by the Food and Drug Administration and is not intended to diagnose, treat, cure, or prevent any disease. We recommend that you consult with a qualified healthcare practitioner before using any herbal products, particularly if you are pregnant, nursing, or on any medications.