IBD Mycobiome: Could Candida Become a Treatable Disease Modifier?: Nature Medicine | September 2026

What Did the Study Find?

This prospective study evaluated 53 patients with mild-to-moderate IBD and concomitant oral thrush, comparing systemic fluconazole with locally acting nystatin during routine care.

Systemic fluconazole reduced intestinal Candida, whereas nystatin did not produce comparable gut effects.

Fluconazole increased bacterial diversity and short-chain-fatty-acid-producing taxa.

Treatment restored several anti-inflammatory microbial metabolites.

The intervention produced durable cross-kingdom changes between fungal and bacterial communities.

These microbiome shifts coincided with improved IBD disease-activity measures and lower short-term progression risk.

Importantly, treatment was not randomized, and follow-up was only 8 weeks.

Why Does It Matter?

The findings move the IBD mycobiome from association toward potential therapeutic manipulation, suggesting that Candida overgrowth may contribute to inflammation in a selected IBD phenotype.

GastroAGI Takeaway

The mycobiome may become a therapeutic target—but fluconazole is not an IBD treatment yet. This small observational study specifically involved Candida-positive patients with oral thrush. Randomized placebo-controlled trials must show that fungal modulation itself improves IBD outcomes before antifungal therapy can enter routine IBD management.