St. John’s Wort is the common name for hypericum perforatum, an herbal remedy for the treatment of depression that has become increasingly popular over the past decade in the United States. It is widely used throughout Europe, Germany in particular, where it is licensed for depression, sleep disorders and anxiety. Herbal remedies are considered a form of alternative medicine.

St. John’s Wort is a yellow flower with five petals that grows wild in many parts of the world. It is named for St. John the Baptist because it blooms around June 24, his feast day. In ancient times, this herbal remedy was believed to have powers to ward off evil spirits.

Treating depression is the most common use for St. John’s Wort. It is also believed by some to be therapeutic in various neurological and immunological disorders (including HIV/AIDS). The mechanism of action is only partially understood at this time and is similar to the prescription medications known as serotonin reuptake inhibitors. Familiar drugs of this class of antidepressants are Paxil, Zoloft, and Prozac.

In some clinical trials, St. John’s Wort has demonstrated effectiveness as an antidepressant when compared to a placebo (sugar pill) or doses of many types of antidepressants. Dozens of research studies have been conducted and published throughout the world on the efficacy of this herb. Although some studies have not shown efficacy for St. John’s Wort, these studies are in the minority and have design issues (for instance, the linked study also showed no positive effect of an FDA-approved antidepressant medication on study participants).

In early 2005, the British Medical Journal published an article demonstrating that in a large clinical trial, St. John’s Wort is at least as effective as a commonly-prescribed antidepressant and has fewer side effects in the treatment of moderate to severe major depression (BMJ 2005;330:503 (5 March)). In 2008, the Cochrane Collaboration — a non-profit research organization that analyzes scientific studies to draw conclusions from them — determined that the overall body of research evidence for the effectiveness of St. John’s Wort in the treatment of depression was strong.

Cochrane Researchers reviewed 29 trials which together included 5,489 patients with symptoms of major depression. All trials employed the commonly used Hamilton Rating Scale for Depression to assess the severity of depression. In trials comparing St. John’s wort to other remedies, not only were the plant extracts considered to be equally effective, but fewer patients dropped out of trials due to adverse effects.

Are Herbal Remedies Safe?

In general, yes, herbal remedies are safe when purchased from a major retail outlet. Herbal remedies have come a long way in the past decade, as their formulations have become more standardized across manufacturers. Herbal remedies still are not regulated in the same manner as prescription medication, however, so they may not adhere to the same stringent requirements. Herbal remedies are considered “food.”

You should always carefully read the herb packaging and ensure you understand the specific type and amount of the herb you’re intending to take. As pointed out in a recent medical journal article, contamination, mislabeling, and misidentification of herbs are important problems. In general, if you are taking an herbal remedy or thinking about it, discuss it with your physician. This is particularly important if you have several medical illnesses and are taking prescription medications.

What Is the Recommended Dose of St. John’s Wort for Depression?

Although this is still under consideration, the recommended doses are based on the doses used in the clinical trials that demonstrated some effectiveness of the herb in depression. Generally, the recommended dose for St. John’s Wort is either 300mg three times each day or 450mg twice a day of standardized extract (standardized to 0.30 percent hypericum, the active ingredient of St. John’s Wort). Talk to your doctor first to determine the right dose for you.

St. John’s Wort Side Effects

Dry mouth, dizziness, constipation, nausea and confusion have been reported by some of the study patients. These were considered to be relatively minor. However, if you experience any of these problems, you should consult your physician and make sure it is okay to continue taking the St. John’s Wort.

Pregnant women are warned against taking St. John’s Wort, as it may affect the muscle tone of the uterus. Also, patients already on prescription antidepressants are advised not to take St. John’s Wort, as drug-to-drug interactions are possible.