Stool pills made from the faeces of donors who are not allergic to peanuts can alter the immune system and increase tolerance to peanuts in allergic individuals, early trial results show.

A single dose of the therapy, called faecal microbiota transplantation (FMT), leads to a significant increase in the reactivity threshold to peanuts at both one month and four months after treatment, according to US researchers at a medical conference last week. 

The phase 1 study findings show that the effect is prolonged, say the team from Boston Children’s Hospital and Harvard Medical School.

“It was rather surprising and very interesting to see that the effect of FMT in patients who showed improvement in their threshold dose of reactivity was prolonged and persistent at four months post FMT,” lead investigator Dr Rima Rachid said in a news release.