St. John's Wort

St. John's wort is a shrubby plant with clusters of yellow flowers that have oval, elongate petals. The plant gets its name because it is often in full bloom around June 24, the day traditionally celebrated as the birthday of John the Baptist. Both the flowers and leaves are used for medicinal purposes.

What's It Made Of?

The best-studied active components are hypericin and pseudohypericin, found in both the leaves and flowers. There has been recent research to suggest, though, that these best-studied components may not be the most active in the plant, which also contains essential oils and flavonoids.

Available Forms

St. John's wort can be obtained in many forms: capsules, tablets, tinctures, teas, and oil-based skin lotions. Chopped or powdered forms of the dried herb are also available. St. John's wort products should be standardized to contain 0.3% hypericin.

How to Take It

The bulk of scientific research on St. John's wort has been conducted in adults. However, one large study (over 100 children under age 12) found St. John's wort to be a safe and effective way of treating mild to moderate symptoms of depression in children. Dosage should be directed by a qualified practitioner and will likely be adjusted according to the weight of the child. Children being treated with St. John's wort should be carefully monitored for side effects such as allergic reactions or digestive upset.

Adult

• Dry herb (in capsules or tablets): The usual dose for mild depression and mood disorders is 300 to 500 mg (standardized to 0.3% hypericin extract), three times per day, with meals.
• Liquid extract (1:1): 40 to 60 drops, two times per day.
• Tea: Pour one cup of boiling water over 1 to 2 tsp of dried St. John's wort and steep for 10 minutes. Drink up to 2 cups per day for four to six weeks.
• Oil or cream: To treat inflammation, as in wounds, burns or hemorrhoids, an oil-based preparation of St. John's wort can be applied topically.

Internal dosages generally require at least eight weeks to get the full therapeutic effect.

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain active substances that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a practitioner knowledgeable in the field of botanical medicine.

Many people take St. John's wort for depression. It is important to bear in mind that depression can be a serious condition and may be accompanied by thoughts of suicide or homicide, both of which warrant immediate medical attention. Evaluation by a healthcare professional should always be sought before using St. John's wort.

Potential side effects from St. John's wort are generally mild. They include stomach upset, hives or other skin rash, fatigue, restlessness, headache, dry mouth, and feelings of dizziness or mental confusion. Although not common, St. John's wort can also make the skin overly sensitive to sunlight (called photodermatitis). Those with light skin who are taking St. John's wort in large doses or over a long period of time should be particularly careful about sun exposure. The use of sunscreen with a skin protection factor (SPF) of at least 15, and the avoidance of sunlamps, tanning booths, or tanning beds is recommended while taking St. John's wort.

Because of the potential for serious interaction with medications used during surgery, patients should discontinue the use of St. John's wort at least 5 days prior to surgery and should avoid taking it post surgery. See Possible Interactions for more information about mixing St. John's wort and medications.

St. John's wort should not be taken by women who are pregnant, trying to become pregnant, or breastfeeding.