Take the Prozac out of your medicine cabinet, says Hester Lacey, and try botany instead. It works for the Germans
HYPERICUM, also known as St John's wort, is a rather dull-looking, stinky plant; its leaves and petals, when crushed or bruised, have a sharp, acrid smell. However, while it may be undistinguished in the garden, it has hidden qualities; extracts from it containing the active ingredient hypericin are being hailed as "nature's Prozac", an effective treatment for depression, insomnia, seasonal affective disorder and pre-menstrual syndrome.

"Although we still don't know how St John's wort works in treating mild to moderate depression, there is no question that it does work," writes Larry Katzenstein in his new book Secrets of St John's Wort (Hodder & Stoughton pounds 7.99). Katzenstein, former medical editor of American Health magazine, cites numerous European clinical tests, "St John's wort is clearly superior to placebos, and appears to be equal in effectiveness to synthetic antidepressants."

The plant has been used for centuries in folk medicine all over the world. As well as its effects on the nervous system it is also a natural antibiotic and anti-inflammatory drug. Hippocrates and Pliny both mention it and Native Americans have used it as a remedy for everything from diarrhoea to snakebite. In modern times, its use is most widespread in Germany, where it outsells Prozac by seven to one. Eighty per cent of German doctors prescribe herbal remedies. According to Katzenstein: "German physicians turn to synthetic antidepressants only after St John's wort products fail to do the job."

In this country, St John's wort is available from health food shops, both in tablet and liquid form; one of the best known brands is marketed under the name Kira. As with many natural remedies, results are not instant; it can take up to six weeks for the effects to kick in. Katzenstein recommends starting a course under the guidance of a doctor (stopping prescription drugs and starting a new kind of remedy without medical supervision is not a good idea).

Although some patients may find it upsets the stomach, there have been no significant discoveries of harmful side-effects. British scientists believe that more research is needed to test its effectiveness for more severe depression, although a report published in the British Medical Journal analysing 23 clinical trials of the plant found it to be "significantly superior" to a placebo and equally effective as standard antidepressants.

St John's wort is rapidly gaining popularity in the US, and Britain may well follow suit. American psychiatrist Harold Bloomfield, author of another book on the subject, Hypericum and Depression, to be published in Britain at the end of this month (Robinson pounds 5.99), says: "We've been using elephant guns to shoot a fly. Why use potent drugs for mild-to-moderate depression if there is something that helps people feel better with fewer side effects, available at a fraction of the cost?"