Between May 2003 and March 2004, 20 doctors in Switzerland undertook a strictly controlled study involving 204 patients using Bioforce Arnica Gel and ibuprofen gel.

Improvement in the two main areas – pain reduction and the functional capacity of the hands – had to be achieved for the study to be successful. In both cases Arnica Gel proved to be as effective as the synthetic gel.

For herbal medicines to be allowed on the register, makers must show that they are safe and manufactured to a high standard. Proof must also be provided that the substance has been used in traditional medicine for many years -- not of efficacy,

"It's shameless," says David Colquhoun, professor of pharmacology at University College London. "Medicines work or don't work, and they should be labelled accordingly."

All EU countries must have similar laws by 2011 in order to comply with a directive on herbal medicines that allows "the requirement to demonstrate efficacy to be replaced by the need to demonstrate traditional use", an MHRA spokesman says.