Evidences Against Herbal Medicines

Sales of herbal medicines today are literally booming. This is mostly true in the United States, where the market for herbal supplements is now in approach. The fastest growth of herbal medicinal treatment has been recorded for St John's wort, an herbal antidepressant whose sales increased in one year by 2800%. Faced with such count the doctors are inclined to ask where the evidence of herbal medicine is. Are there thorough trials to show that herbal treatments really work?

Single studies on herbal medicine are unlikely to encourage sceptics, but an increasing body of evidence is now emerging from systematic reviews and meta-analyses of randomized clinical trials. These suggest that some herbal medicines are efficacious. For instance, the increasing demand for St John's wort was triggered by press reports of a meta-analysis of 23 randomized trials of 1757 patients with mild or moderate depression. The researchers concluded that extracts of hypericum were significantly more effective than placebo, the odds ratio 2.67; 95% confidence interval 1.78 to 4.01 and as efficient as conventional antidepressants, the odds ratio 1.10; 93 to 1.31 in alleviating the signs of mild to moderate depression. Long before, at least nine further randomized trials have made, all of which confirm the efficacy of various herbal antidepressant.



Systematic study and analyses of other herbal medicines followed and drew likewise positive conclusions. A review of the entire placebo controlled, double blind randomized trials of ginkgo biloba for dementia, covering around 1497 patients, showed that ginkgo was more efficient than placebo in delaying the medical course of dementia. A meta-analysis of 18 randomized controlled trials on around 2939 patients of saw palmetto as a symptomatic treatment for benign prostate hyperplasia showed that it improved urological symptoms and flow measures significantly more than placebo. Saw palmetto was as efficient as finasteride and had fewer adverse effects. A systematic study and review of horse chestnut seed extracts for chronic venous insufficiency included eight placebo controlled and five comparative randomized trials with a total of 1083 patients.

Even though various herbal remedies may be effective, do their benefits outweigh the risks? Most of the herbal remedies and supplements in the United Kingdom and United States are sold as food supplements. Thus they avoid regulation of their quality and safety. The minister of UK for the sake of public health recently pointed out that the regime for unlicensed medicines does not give systematic protection to the public against low quality and unsafe unlicensed herbal remedies. Two recent cases of serious nephropathy caused by Chinese herbal tea administered to treat eczema illustrate this.

Huge variations persist in the quality of herbal medicine preparations. For instance, when German commercial products of devil's claw were tested, an unacceptable variability of quality was noted. Yet Germany is often admired for the exemplary standard of quality control of herbal medicines. A very recent survey on herbal creams in the United Kingdom showed that 8 of 11 preparations contained undeclared dexamethasone at a mean concentration of 456 mg/g. The possibility of herbal medicine interactions is a further important and under-researched issue.

• Janny Raines
• 05/01/2009, 6:59 AM
• 0 Comments