The remedy, already a best-seller in the growing herbal-medicine market, improved the mood and mental performance of patients with moderate depression at least as much as the widely prescribed anti-depressant imipramine. Side- effects, such as a dry mouth, were worse in those who took imipramine than in those who took hypericum extract.
The findings, published in the British Medical Journal, were immediately countered with a warning in the rival journal The Lancet that hypericum extract may be less safe than its "natural" label encourages consumers to think.
Edzard Ernst, professor of complementary medicine at the University of Exeter, writes in The Lancet that at least eight cases have been reported of St John's Wort reacting badly with pharmaceutical drugs that patients were taking, reducing their effectiveness and increasing side-effects.
Professor Ernst says patients should be encouraged to tell their doctors if they are taking alternative remedies and to recognise that "natural" does not always mean "harmless".
"Given the widespread use of hypericum extracts, the implications of emerging evidence of adverse reaction are potentially serious," Professor Ernst writes. "Regulatory bodies should perhaps take a fresh look at whether herbal medicines need regulation.
The BMJ study was conducted by researchers from Germany, where hypericum extracts outsell Prozac by four to one. Scientists at the Imerem Institute for Medical Research in Nuremberg compared hypericum extracts with imipramine in 263 patients. They found the herbal remedy as effective as the pharmaceutical. "Since many depressed patients receive either no treatment or inadequate treatment," they write, "hypericum extract may be considered as an alternative first choice."Reuse content