Researchers in a small clinical trial found that swallowing capsules containing stool from allergy-free donors reduced peanut allergies in six adults with severe peanut sensitivity. The trial used faecal microbiota transplantation, a procedure that transfers beneficial bacteria from healthy donors to patients.

Participants consumed capsules of freeze-dried faecal matter over several weeks, allowing gut bacteria from the donors to colonize their intestines. The treatment aimed to reprogram immune responses that trigger allergic reactions to peanuts.

Before treatment, the six adults could tolerate only tiny amounts of peanut protein, sometimes less than a single peanut. After the transplantation procedure, all six participants showed improved tolerance, able to consume significantly larger quantities without severe reactions. The improvements persisted for months following treatment.

The mechanism appears to involve restoring bacterial diversity in the gut microbiome. People with peanut allergies often have less diverse bacterial communities compared to allergy-free individuals. The transplanted bacteria likely help educate immune cells in the intestines to tolerate peanut proteins rather than mounting allergic attacks.

This work builds on earlier research linking gut microbiota composition to food allergy development. Previous studies showed that children with food allergies have distinct microbiome profiles compared to tolerant peers.

However, the trial involved only six participants, limiting confidence in the findings. Larger, controlled studies are needed to confirm efficacy and establish optimal dosing protocols. Safety profiles also require scrutiny, particularly regarding potential transmission of infectious agents through faecal transplants, though capsule processing typically includes safety measures.

The approach represents a novel therapeutic direction for severe food allergies, which affect roughly 2 percent of adults. Current treatments rely primarily on avoidance or emergency epinephrine auto-injectors. If larger trials prove successful, faecal microbiota transpl