There is no reliable way for the public to identify those which could be unsafe

Professor Alastair Breckenridge, MCA

However, MCA checks have also uncovered poisonous heavy metals such as mercury and arsenic, and prescription only steroids which could be damaging if taken over long periods.

Now it is proposing to increase safety by lengthening the list of substances banned in traditional Chinese medicines.

Professor Alastair Breckenridge, its chairman, said that consumers should steer well clear of any remedies which were not fully labelled with a list of ingredients.

"I am concerned we continue to find further examples of traditional Chinese medicines containing potentially dangerous and often illegal ingredients.

"There is no reliable way for the public to identify those which could be unsafe. We are unable to give the public any general assurances as to the safety of traditional Chinese medicines on the UK market."

There are currently thought to be approximately 600 state-registered Chinese herbalists at work in the UK, carrying out at least 1m consultations a year.

Open season

Michael McIntyre, chairman of the European Herbal Practitioners Association, admitted that the sector was completely unregulated.

"Anyone can set themselves up as a herbalist," he said.

"Clearly that is not in the interests of the public who can become hostages to fortune."

Since the 1999 Health Act, it is possible for herbalists to become state registered, although there is nothing to stop anyone practising herbal medicine.

Herbal medicines are not subject to the normal strict quality controls applied to pharmaceuticals.

In a joint statement, the Register of Chinese Herbal Medicine, the Association of Traditional Chinese Medicine, the Chinese Medical Institue and the Society of Chinese Medicine (UK) said that quality control was "paramount".

"Disciplinary action will be taken against any member of our associations who is found to be putting the public at risk."