Doctors have said they could treat peanut allergy by feeding children the very thing their bodies reject, so building tolerance that could save a life in case of accidental ingestion.
Small doses of peanut powder taken over several months seemed to induce tolerance in children with the potentially deadly allergy, a research team wrote yesterday in The Lancet medical journal.
After six months of treatment, dubbed oral immunotherapy or OIT, 84-91% of the children in a trial could safely tolerate daily doses of 800mg of peanut powder - the equivalent of about five peanuts.
This was 25 times the amount they could tolerate before the therapy, and much larger than any accidental dose is likely to ever be.
"The treatment allowed children with all severities of peanut allergy to eat large quantities of peanuts, well above the levels found in contaminated snacks and meals, freeing them and their parents from the fear of a potentially life threatening allergic reaction," said study leader Andrew Clark from Cambridge University Hospitals.
"The families involved in this study say that it has changed their lives dramatically."
The trial involved 99 allergic children aged seven to 16.
One in five of the kids receiving OIT reported "adverse events", mostly mild itching of the mouth, the authors said.
They stressed that people should not try the treatment at home as more research was needed.
Peanut allergy affects about one in 50 children and is the most common cause of fatal food allergy reactions.
About 10 million people around the world are allergic to peanuts.
Symptoms vary from mild to severe, from swollen lips or shortness of breath to anaphylactic shock, which can be fatal.
While "exceptionally promising", the method remains experimental, Matthew Greenhawt from the University of Michigan Food Allergy Center wrote in a comment also carried by The Lancet.
"It is unknown if OIT can produce lasting tolerance," he wrote.