London - A tiny daily dose of liquid peanut protein could save children from severe reactions to the food, doctors said.
Their trials on 48 highly allergic under-12s found that two thirds became able to tolerate small amounts of peanuts.
A quarter were even able to eat up to 20 kernels. Typically a tenth of a kernel would be enough to spark a reaction.
The under-the-tongue treatment could stop children falling ill from accidental exposure at a restaurant or a party.
"As a parent of two children with nut allergies, I know the fear parents face," said Edwin Kim, who led the University of North Carolina research reported in the Journal of Allergy and Clinical Immunology.
"We now have the first long-term data showing that sublingual immunotherapy is safe and tolerable while offering a strong amount of protection."
The rate of peanut allergy in Western children has doubled in a decade, making it the most common food allergy – affecting one in 40 youngsters. It is caused when the immune system mistakenly treats peanut protein as a threat.
This can cause hives, facial swelling or life-threatening anaphylaxis, which may lead to breathing difficulties, a raised heartbeat and collapse.
The treatment is one of three being trialled to protect children from the allergy.