How safe are herbal remedies?

Hundreds of herbal remedies could soon lose their licences as the latest EU directive on these medicines proceeds. Remedies are being looked at for safety, quality and the length of time that they have been on sale, which will enable fewer wild claims to be made about particular products. Last week, the National Institute for Medical Herbalists warned some of these products, if misused, can do more harm than good. Some herbs interact with certain prescription drugs, such as the anti blood-clotting agent Warfarin; others don't suit some people. Alison Denham, a former president of the institute, who helped to compile this table, urges particular caution when using herbal slimming products. "If in doubt, don't self-medicate, go and see a trained herbal practitioner."

Aristolochia

BANNED

Uses: Traditional Chinese medicine has used it for thousands of years without serious side-effects, but it has recently been mistaken for other herbs with similar names in slimming preparations and for treating skin conditions.

Dangers: In 1993, it was implicated in renal failure in patients at an upmarket Belgian slimming clinic, and similarly in Britain in 1999. It should on no account be available in this country.

Echinacea

Uses: Popular as an immune booster, it is particularly useful for increasing resistance to infections in people with chronic fatigue syndrome. Possibly overrated. It's good, but not a miracleworker.

Dangers: Has a very good safety record, but shouldn't be used by people with an auto-immune disease such as rheumatoid arthritis or HIV. Don't take continually or it may prove counterproductive by suppressing the immune system.

Ephedra

BANNED

Uses: This stimulant acts like an amphetamine. Can be used in low doses by herbal practitioners who are licensed to use it under the 1968 Medicines Act, but should not be available over the counter. It is still found in American products, which can be bought over the internet.

Dangers: As do other stimulants, ephedra can increase the heart rate and make people feel "speedy". If taken in high doses it could lead to a heart attack in a susceptible person.

Ginkgo Biloba

Uses: Good for circulation. Trials show it eases Raynaud's disease (where hands go white with cold) and also helps people with intermittent claudication (which is like angina in the calves) to walk for longer periods without feeling pain.

Dangers: People using blood-thinners - including aspirin and Warfarin - should steer clear of Ginkgo.

Ginseng

Uses: To improve concentration and alertness. As a general health-booster, it is best used by people who've been ill or are convalescing, or by people who are under stress from, say, too much air travel or working night shifts.

Dangers: Its safety record is very good, but it doesn't work for everyone. Don't be tempted by cheap products; these tend to have very little ginseng in them.

Guarana

Uses: To boost mental alertness and focus. Its effect is more similar to a shot of caffeine, rather than speed. It is widely available (Cadbury's latest chocolate bar is called Boost Guarana).

Dangers: Be cautious - just because something is natural, warns Denham, it may not be a good idea. Caffeine, in the form of a cup of coffee, is also natural, but it can be habit-forming.

Kava

BANNED

Uses: To treat insomnia. Also useful in alleviating pain related to muscle tension. Herbal practitioners find it very effective, although they don't use concentracted standardised products but extracts of the herb.

Dangers: In rare cases where people have been using the concentrated standardised form of the product, which is available over the counter, it has led to liver damage. This led to a voluntary ban by suppliers and herbalists, which came into force in December 2001.

Licorice

Uses: As a tonic for general well-being.

Dangers: Should be avoided by people taking medicines for hypertension (high blood pressure) because the herb can cause water retention, especially at higher doses. Anyone taking long-term medication should see a herbal practitioner, rather than buying remedies over the counter.

St John's Wort

Uses: To alleviate depression, anxiety, and as a mood-lifter for conditions such as PMT. Again, herbal practitioners use tinctures and extracts, rather than the standardised product available in shops.

Dangers: Taken alone, it causes no problems. However, it has been shown to interact with certain orthodox drugs: the Pill, cyclosporin (for transplant patients) and HIV drugs. It is also not recommended for use with orthodox anti-depressants because the two can speed up each other's action.

Valerian

Uses: Insomnia and anxiety, such as pre-exam nerves.

Dangers: Again, a herb which doesn't suit everybody. Oddly, it can have the opposite effect to that intended, causing twitches or headaches. It can make some people feel lethargic. Some people have overdosed with Valerian but they've slept it off.

To find a qualified practitioner, call the National Institute of Medical Herbalists on 01392 426 022.