St. John’s Wort

What Is It

A shrubby perennial bearing bright yellow flowers, St. John’s wort is cultivated worldwide. It was named for Saint John the Baptist because it blooms around June 24, the day celebrated as his birthday; “wort” is an old English word for plant. For centuries, St. John’s wort was used to soothe the nerves and to heal wounds, burns, and snakebites. Supplements are made from the dried flowers, which contain a number of therapeutic substances, including a healing pigment called hypericin.

What Does It Do

St. John’s wort is most often used to treat mild depression. Scientists aren’t sure exactly how the herb works, though it’s believed to boost levels of the brain’s chemical serotonin, which is key to mood and emotions.

Common Uses

  • Treats depression.
  • Helps fight off viral and bacterial infections.
  • May help treat premenstrual syndrome (PMS) and fibromyalgia.
  • Helps relieve chronic pain.
  • Soothes hemorrhoids.
  • May aid in weight loss.

Major Benefits

A careful recent analysis of 23 different studies of St. John’s wort concluded that the herb was as effective as antidepressant drugs and more effective than a placebo in the treatment of mild to moderate depression. (Few studies have examined its usefulness for more serious depression, though it may prove beneficial for this as well.) St. John’s wort may be helpful for many conditions associated with depression too, such as anxiety, stress, premenstrual syndrome (PMS), fibromyalgia, or chronic pain; it may even have some direct pain-relieving effects. This herb promotes sound sleep and may be especially valuable when depression is marked by fatigue, sleepiness, and low energy levels. It may also aid in treating “wintertime blues” (seasonal affective disorder), a type of depression that develops in the fall and winter and dissipates in the bright sunlight of spring and summer.

Some people are leery of conventional antidepressants because of their potential for causing undesirable side effects, especially reduced sexual function. St. John’s wort has fewer bothersome side effects than these drugs. In addition, although St. John’s wort may interact with antidepressant medications, it doesn’t appear to interact with most other conventional drugs, making it useful for older people taking multiple medications. The herb seems so promising that the National Institutes of Health (NIH) is now conducting a major study of its effectiveness.

Additional Benefits

St. John’s wort fights bacteria and viruses as well. Research indicates that it may play a key part in combating herpes simplex, influenza, and Epstein-Barr virus (the cause of mononucleosis), and preliminary laboratory studies reveal a possible role for the herb in the fight against AIDS. When an ointment made from St. John’s wort is applied to hemorrhoids, it relieves burning and itching. Taken along with the herb ephedra, St. John’s wort may also be useful as a weight-loss aid.

How To Take It


The recommended dose is 300 mg of an extract standardized to contain 0.3% hypericin, three times a day. Supplements containing 450 mg are also available and can be taken twice a day.

Guidelines For Use:

Take St. John’s wort close to mealtime to reduce stomach irritation. In the past, those using the herb were advised not to eat certain foods, including aged cheese and red wine, the same foods best avoided by those taking MAO inhibitors (a type of antidepressant). But recent studies suggest that these foods do not present a problem for those on St. John’s wort.
Like a prescription antidepressant, the herb must build up in your blood before it becomes effective, so be sure to allow at least four weeks to determine whether it works for you. It can be used long term, as needed. Unless you are under the care of a doctor familiar with both conventional antidepressants and St. John’s wort, the medication and the herb should not be taken together because of the potential for adverse reactions. Some doctors also recommend combining St. John’s wort with the nutritional supplement 5-HTP.
Though no adverse effects have been reported in pregnant or lactating women using the herb, there have been few studies in this group of patients, so caution is advised.

Latest Findings

  • In one recent study, 50 participants with depression were given either St. John’s wort or a placebo. After eight weeks, 70% of those on St. John’s wort showed marked improvement, versus 45% of those receiving a placebo. No adverse reactions to the herb were noted.
  • Although used for mild and moderate depression, St. John’s wort may one day prove effective for more severe cases. A study of 209 people with serious depression found the herb as effective as conventional antidepressants. But more research is needed before the supplement can be recommended for this purpose.


  • If you’re taking conventional antidepressant drugs, consult your doctor before adding or switching to St. John’s wort.
  • If you develop a rash or have difficulty breathing (rarely, people have allergic reactions), get immediate medical help.

Leave a Reply

Your email address will not be published. Required fields are marked *