Scientists are looking for volunteers to help them find a cure for allergies - by injecting them with hookworms.
The tiny worms would be injected into the bloodstream
Researchers at Nottingham City Hospital need 60 volunteers who suffer from allergies to carry hookworms.
The tests, based on research done in Africa, could help cure people with over-sensitive immune systems.
Doctors believe people carrying the parasite have a reduced risk of allergies because their immune system is "distracted" by the worm.
John Britton, a professor of epidemiology at Nottingham City Hospital, who has done research in Ethiopia, discovered people living in the countryside are less likely to have allergies but more likely to have parasites.
"We found higher levels of asthma in the towns and we believe this was partly down to a lower number of people carrying parasites," he said.
For the research, volunteers will receive 10 Papua New Guinea strains of the worm, which can grow up to a centimetre long.
"We are trying to find out if we can use the worms or their products to lesson the impact of allergies," Prof Britton said.
"The worms pass into the bloodstream before being trapped in the lungs.
"They are then coughed up and swallowed into the stomach, then the bowels, where they breed before the larvae pass out of the body. "
Researchers think some kinds of hookworm secrete proteins which can damp down the immune response that causes asthma.
Leshie Chandrapala, 25, from Forest Fields, who suffers from asthma, said he would think twice before taking part in the tests.
"I find my asthma is often linked to stress and I have not been that stressed recently," he said.
"I would also want to know a bit more about it before treatment like that."
Researchers have already tested the worms on themselves to find the appropriate dosage.
The £250,000 research project is looking for 30 asthma sufferers and 30 hayfever or allergy suffers for the 12-week trial.