St. John's Wort

Hypericum perforatum · Hypericum · SJW

Snapshot

Indications	Contraindications
Mild to moderate depression¹ Menopausal symptoms² Topical wound healing³ Somatic symptom disorder⁴	Blood thinners⁵ Hormonal contraceptives⁵ Immunosuppressants⁵

St. John's wort (Hypericum perforatum) is a yellow-flowered plant used in Greek, Islamic, and Chinese traditional medicine⁴. Its extracts act on several neurotransmitter systems, chiefly reuptake inhibition⁶. Supplementation is used mainly for mild to moderate depression, and also for menopausal symptoms and topical wound care, where the trials are fewer. The typical patient is an adult with mild to moderate depression seeking an alternative to prescription antidepressants.

A systematic review found extracts superior to placebo and comparable to antidepressants in mild to moderate depression, with fewer adverse events than antidepressants, though adverse event reporting was limited¹. Evidence for severe depression and longer-term use is limited, and one trial in major depression found no benefit over placebo⁷. In a 2025 two-group comparison after upper eyelid surgery, topical Hypericum perforatum extract improved early wound healing scores without a lasting effect on scars³. Products are sold as capsules, tablets, liquids, and teas, with standardized extracts differing from whole herb; see Form comparison.

The most consequential caution is pharmacokinetic: long-term use induces intestinal cytochrome P450 3A (CYP3A) activity, lowering exposure to many co-administered medicines^{8, 9}. The National Center for Complementary and Integrative Health asks anyone taking prescription medicines to talk with a health care provider first⁴.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

96 sources, 83 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources