Prof Monique Simmonds, a plant chemist at Kew Gardens, on the medicine's toxicity
A practitioner of Chinese medicine has pleaded guilty to selling a banned substance to a woman who went on to develop kidney failure and cancer.
Ying "Susan" Wu, 48, of Holland-on-Sea in Essex, has been on trial at the Old Bailey for selling pills containing aristolochic acid to a civil servant.
The judge said he accepted Ms Wu had not meant to harm, and that the case highlighted the need for regulation.
Ms Wu has now been given a conditional discharge.
Patricia Booth, 58, took the pills, bought at Chelmsford's Chinese Herbal Medical Centre, for over five years. She was in her mid-40s when she first sought help from the centre in 1997 for stubborn patches of spots on her face.
The Old Bailey heard the products had been advertised as "safe and natural".
But they contained a substance - aristolochic acid - which when she was first sold them, should only have been given under prescription, and which was later banned.
Traditionally this would be used maybe once or twice by a doctor who would know about its toxicity, but sometimes it might get into a formulation which is then used by somebody who doesn't have this wealth of experience
Professor Monique Simmonds
The court heard Mrs Booth became ill months after she stopped taking the pills. She was diagnosed with kidney failure, and later with cancer of the urinary tract - both allegedly caused by the pills.
The grandmother, who used to manage a government office of up to 60 people, currently goes to hospital three times each week for dialysis.
She had told the court that she had been advised to take about 30 tiny brown tablets three times each day, returning to the shop every two weeks to buy up to three bottles at a time. She became friendly with Ms Wu, who was employed at the shop as a "Chinese doctor" until it closed in 2003.
Ms Wu, who had initially denied the charges, pleaded guilty to selling prescription only medicines without authorisation and to selling a banned substance.
But an Old Bailey judge ruled that, as the sale of traditional Chinese medicines was totally unregulated, there was no evidence that she knew of the potential harm. A charge of "administering a noxious substance so as to endanger life or inflict grievous bodily harm" was therefore thrown out.
"Everybody accepts that you didn't know you were breaking the law," he told Ms Wu.
He added that while the medicine watchdog, the MHRA, tried to make everyone aware of dangers attached to this herb, "it is not a foolproof system and I am certainly not blaming you for the fact you didn't know about these regulations".
"This means the degree of culpability is very small."
The Register of Chinese Herbal Medicine, which represents more than 450 practitioners, said the case highlighted "the urgent need for the statutory regulation of herbal medicine in the UK".
Statutory regulation would ensure that anyone who practises Chinese herbal medicine is suitably qualified and competent, and that all suppliers of herbal medicine are licensed
The Register of Chinese Herbal Medicine
The Department of Health is currently considering recommendations for just such regulation, but it is unclear when such a framework will come into force.
Aristolochic acid was banned in July 1999, having previously been available as a prescription-only drug.
It is a common feature of Chinese medicine, but experts say experienced traditional practitioners would only ever use it sparingly.
There have been recorded incidents of the acid - which has been used for a host of conditions from procuring abortions to treating indigestion - causing kidney problems and cancer in the past.
The most high-profile cases involved 100 incidents of renal disease among patients at a weight loss clinic in Belgium between 1990 and 1992. Most required either dialysis or transplantation, while a few died from consumption of the weight-reducing herb.
Professor Monique Simmonds, head of biological interactions at Kew, who examined the pills sold to Mrs Booth, said one of the problems with this substance was that it was unclear at what dose it began to build up in the human body and cause health problems.
The judge said there was no proof Wu knew of the harm she was causing
"Traditionally this would be used maybe once or twice by a doctor who would know about its toxicity, but sometimes it might get into a formulation which is then used by somebody who doesn't have this wealth of experience," she said.
"Traditional Chinese medicine does have a place in the cocktail of medicine available to us, but is is really important we have some kind of regulation - not just in terms of the plant but also the practitioner."
Emma Farrant of the The Register of Chinese Herbal Medicine, said statutory regulation of all practitioners of herbal medicine "would ensure that anyone who practises Chinese herbal medicine is suitably qualified and competent."
"Statutory regulation would also ensure that the quality and supply of herbs is tightly controlled under arrangements proposed by the Medicines and Healthcare products Regulatory Agency."
Tracey Brown, managing director of Sense About Science, said: "This case does not show that we need more regulations.
"What this case does show is the need to make a clearer distinction between therapies that are effective and deemed safe for use - medicine - and those which aren't. It shows the need for proper medical training.
"This is why Sense About Science has objected to Department of Health proposals to introduce a professional registration scheme for herbalists and other practitioners of 'traditional' medicine.
"Such a scheme would encourage further the idea that practising medicine does not need to involve proper medical training."
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