Recent trials of a drink containing thousands of pig whipworm eggs appeared to significantly reduce symptoms of IBD, such as abdominal pain, bleeding and diarrhoea, in study participants.

Indeed, among 100 volunteers with Crohn's disease and 100 with ulcerative colitis, both of which are diseases classified under IBD, the remission rate was 70% and 50%, respectively, after the treatment.

Dr Joel Weinstock, from the University of Iowa, who devised the treatment, told New Scientist magazine: "A lot of researchers couldn't believe this treatment was effective, but people are always sceptical when confronted with new ideas."

He thought of treating IBD with worms after noticing that a significant increase in the disease in developed countries coincided with a sharp fall in the number of parasitic infections, such as human whipworm and roundworm. Incidence of IBD is still rare in countries where parasitic infections remain common.

Dr Weinstock's theory was that the human immune system has evolved to tolerate the presence of parasites, and without them it can become overactive.

Pig whipworm, instead of human whipworm, was chosen for the treatment as it does not survive very long in people.

A German company called BioCure, whose sister company BioMonde produces leeches and maggots for treating wounds, is producing a version of the concoction called TSO, after the Latin name for the worm Trichuris suis ova. Chief Executive Detlev Goj said that TSO could soon be available in Europe, pending approval by the European Agency for the Evaluation of Medicinal Products.

Dr Weinstock will announce the results of the latest clinical trials in May at a conference in New Orleans, Louisiana, USA.