St. John’s Wort (Hypericum perforatum)

St. John’s Wort: Medical Uses

St. John’s wort is taken orally for mild to moderate depression, not for severe depression or bipolar disorder. It can be used externally for tennis elbow, sprains, and strains.

Historical Uses

St. John’s wort was used by the ancient Greeks for sciatica and nervous disorders. It has also been used as a popular folk remedy for neuralgias, sciatica, burns or bruises involving nerve damage, sprains, emotional disorders, wounds, and tennis elbow.


This plant grows in fields and on roadsides throughout the United States. It reaches about 1 to 3 feet in height, and its yellow flowers bloom from June to September.

Parts Used

• Aerial (above-ground) parts

Major Chemical Compounds

• Hypericin

• Hyperforin

• Flavonoids

St. John’s Wort: Clinical Uses

St. John’s wort is given orally for mild to moderate depression, not for severe depression or bipolar disorder. It can be used externally for tennis elbow, sprains, and strains. It is approved by the German Commission E to be used “internally for depressive moods, anxiety, externally for acute and contused injuries, myalgia, and first-degree burns”.

St. John’s wort is at least as safe as, and possibly safer than, fluoxetine (Prozac) (); moclobemide, a monoamine oxidase inhibitor; dothiepin, a tri-cyclic antidepressant; and mirtazapine, a noradrenergic and specific serotonergic anti-depressant.

Mechanism of Action

It is unknown which constituent is responsible for the antidepressant effects. Hyperforin inhibits the uptake of serotonin, dopamine, noradrenaline, gamma-aminobutyric acid, and L-glutamate.

St. John’s Wort: Dosage

Capsules: 300 to 900 mg daily. Small children should receive a total of 300 mg daily, large children 600 mg daily, and adolescents the full adult dose. To determine effectiveness, the treatment period should last 4 to 6 weeks. Standardize to a hypericin content of 0.3 percent (); some forms are standardized to 5 percent hyperforin.

Tincture: 20 to 30 drops three times daily.

Herbal oil: Massage oil into skin for tennis elbow, sprains, and strains.

Side Effects

Two cases of photosensitivity at high doses have been documented in humans. Larger-than-normal doses of St. John’s wort have been known to cause dermatitis of the skin and inflammation of the mucous membranes after exposure to sunlight.


• Do not give St. John’s wort to patients with chronic or severe depression.

Herb-Drug Interactions

St. John’s wort should not be given with selective serotonin reuptake inhibitors, nonsedating antihistamines, oral contraceptives, anti-retrovirals, anti-epileptics, calcium channel blockers, cyclosporine, chemotherapeutics, macrolide antibiotics, or antifungals. It may interfere with the metabolism of drugs used by AIDS patients and heart transplant patients. Do not give St. John’s wort with any other antidepressant. After discontinuing a previous antidepressant, allow 2 weeks before starting St. John’s wort, and taper the dosage.

Pregnancy and Breast-Feeding

No restrictions are known.

Summary of Studies

Schrader (2000). A randomized, controlled, 6-week German study of 242 outpatients compared St. John’s wort to fluoxetine (Prozac). Of those, 114 patients took 20 mg of fluoxetine b.i.d. and 128 patients took Ze 117 hypericum extract tablet (Zeller, Switzerland) at 250 mg b.i.d. Results: St. John’s wort had far superior safety and fewer, milder side effects than fluoxetine. The only side effect of St. John’s wort was mild gastrointestinal upset.

Linde & Mulrow (1999). This meta-analysis included 27 random trials of 2291 participants. Results: There is evidence that extracts of hypericum are more effective than placebo for the treatment of mild to moderately severe depressive disorders.

Harrer & Schulz (1994). This report used 25 controlled clinical studies with 1592 subjects who took 300 to 900 mg for 2 to 6 weeks. Results: Hypericum was effective in the treatment of patients with mild to moderate depression. Studies indicate a high degree of efficacy and tolerability

Sommer & Harrer (1994). This placebo-controlled, double-blind study included 89 subjects taking 300 mg t.i.d. for 4 weeks. Results: differences between active and placebo groups were statistically significant after 2 and 4 weeks; 67 percent of the active group responded to treatment, whereas 28 percent responded to the placebo.

Hubner & Kirste (2001). In a multicenter surveillance study, 101 children under 12 years old treated for 4 to 6 weeks with Hypericum perforatum at doses ranging from 300 to 1800 per day. Results showed that St. John’s wort was safe and effective in treating mild depression and was without side effects.


• St. John’s wort may cause a rash in fair-skinned people.

• Larger-than-normal doses of St. John’s wort may cause skin irritation and inflammation of the mucous membranes with exposure to sunlight.

• Don’t take St. John’s wort if you have chronic or severe depression.

• Consult with your health-care practitioner before using St. John’s wort if you take any prescription medications, especially antidepressants, over-the-counter antihistamines for cold and allergy symptoms, oral birth control pills, HIV or AIDS medications, seizure medications, some heart medications, some antibiotics, and chemotherapy agents.

St. John’s Wort: Recipes

Massage Oil (Herbal Oil Infusion) For Strains And Sprains

Pick the buds of St. Johns’ wort when the leaves are dotted with red spots (your fingers will turn red as you pick them). Place the buds (either dry or wilted) gently into a container and cover with extra virgin olive oil (thicker than other oils), or almond, sunflower, or safflower oil. Make sure that none of the plant parts extend above the oil or the oil will become moldy. Shake the jar daily. Place in a sunny area and in about 2 weeks the oil will turn red. Strain the herb into a dark bottle and use the oil all winter for any type of strain, sprain, backache, or sports injury.