Zileuton Shows Promise Against Peanut Allergy Reactions

Northwestern researchers found an asthma drug reduced severe allergic reactions in mice exposed to peanut extract.

Updated on Nov. 7, 2026 in Allergies

Clear unlabeled glass vials of pale amber liquid and a small pipette rest on a steel laboratory bench in soft daylight. — Researchers at Northwestern University found that the asthma drug Zileuton reduced severe reactions to peanut extract in mice, opening a possible new path for food allergy treatment. AI Illustration. Upload story photo >

Researchers at Northwestern University found that mice given Zileuton, an FDA-approved asthma drug, showed few symptoms after exposure to peanut extract. The study marks the first time Zileuton has been examined in the context of food allergies.

Why it matters

The findings point to a biological pathway linking the gut to anaphylaxis, and only two FDA-approved treatments currently exist for food allergies. With more than 33 million people in the United States affected by at least one food allergy, a repurposed drug could expand treatment options.

In a mouse study, 95% of animals given Zileuton were protected from severe allergic reactions, but results from mice do not confirm effects in people. Researchers have not yet reported human efficacy data from the phase one trial launched in 2025.

The players

Northwestern University

A private research university in Evanston, Illinois, whose researchers conducted the study on Zileuton and peanut allergy.

Zileuton

An FDA-approved drug originally used to treat asthma by blocking leukotriene production.

The details

Zileuton works by blocking the body from producing leukotrienes, inflammatory molecules that help allergens pass through the gut wall into the bloodstream. A 2025 study in the journal Science identified the gene DPEP1, which codes for an enzyme that breaks down leukotrienes, as relevant to peanut allergen absorption.

2025: Northwestern study published and phase one human trial launched.
2025: Science journal study on DPEP1 and leukotrienes published.

Health Landscape

The study extends the search for food allergy treatments beyond the two currently FDA-approved options. Repurposing an existing asthma drug could offer a faster route than developing a new therapy from scratch.

Zileuton is not yet prescribed for allergies, and it could be years before that changes. Anyone managing a food allergy should continue following current medical guidance rather than seeking this drug off-label.

The takeaway

Researchers have uncovered a gut-based pathway that may be targeted to reduce severe food allergy reactions. Results in mice are promising, but human confirmation is still needed before any clinical change.