Ancient Greeks and Romans believed it warded off evil spirits and witches' spells. Europeans found Native Americans using it for diarrhea and snakebite. But modern America had largely ignored St. John's wort -- the yellow-flowered weed that's sprouted unnoticed in roadside ditches and on sunshine-splashed hillsides.
In 1997, America stopped ignoring. Suddenly, health food stores and nutrition centers can't keep the herb on their shelves. And, while no one mentions protection from witches' spells these days, respected doctors and scientists say St. John's wort is -- and always has been -- an invaluable antidepressant. Nature's own Prozac, in a way -- without the expense or the troubling side effects.
German doctors have prescribed St. John's wort in tablet form for 15 years, making it the dominant antidepressant there, much more popular than Prozac. Over 20 million Germans take it daily.
Two dozen European studies confirm that the herb works as well as, or better than, antidepressant drugs -- showing that 50 to 80 percent of depressed patients improved while taking the herb, which is about the same as with antidepressant drugs. The main difference: While antidepressant drugs often come with significant side effects, such as insomnia and reduced sex drive, St. John's wort -- also known by its Latin name, hypericin -- rarely causes side effects.
When side effects have occurred, they've been relatively minor. Dr. Harold Bloomfield, a Yale-trained psychiatrist and one of the more well-known proponents of St. John's wort, says hundreds of his patients take it. "While it's not a panacea, it is at least as effective as synthetic antidepressants," he says. "And people like it."
The American medical establishment has maintained, however, that the European studies were not extensive enough. But interest has unquestionably been piqued: Major U.S. studies are now underway.
If you're interested in trying St. John's wort, you need to know a few things. (Besides how it got that strange name: "wort" is Old English for "plant" and the "St. John's" may come from when the plant's flowers bloom -- around the Feast of St. John in late June.)
While no prescription is required, and its is sold at health food stores and nutrition centers, products labeled St. John's wort can vary significantly in strength. Doctors recommend three daily doses of 300 milligrams of an extract containing 0.3 percent hypericin. (The hypericin content is how the herbal extract is measured, although a number of chemical components may combine to make St. John's wort work.)
The herb won't work for everyone. It has proven effective only for people with minor or moderate -- not severe -- depression. And no one should switch from doctor-prescribed antidepressants to St. John's wort without first talking to your doctor.
Be aware of these unresolved questions about St. John's wort: Some doctors say it can increase sensitivity to the sun for some people, and that, because of how the herb might work, people taking St. John's wort should avoid foods high in a substance called tyramine -- foods like red wine, dried meat, and cheese. Other experts, however, say there is no evidence that St. John's wort has ever caused sun-sensitivity in humans, and point to studies that refute the tyramine problem.
Most important, even people who might be helped by St. John's wort need to be patient; its effects are mild. You should take it for at least six weeks before judging whether it's helping, Bloomfield says. Those searching for new help with their depression can perhaps afford to be patient: The proper St. John's wort dose costs $10 to $30 per month. For the thousands who say the herb has helped them -- and who were accustomed to paying hundreds of dollars per month for antidepressants -- that's a bargain.