The review article ‘Tracking microbiota fibre breakdown to treat NASH’ (doi: 10.1038/s41564-023-01440-9) has recently been published in the journal Nature Microbiology. Its authors are Alejandra Flor, Marta Olivares and Yolanda Sanz from the Microbiome, Nutrition and Health unit at IATA-CSIC. The article evaluates how the interaction between the intestinal microbiota of mice and inulin, a soluble dietary fibre naturally present in foods such as artichokes, asparagus, onions and leeks, generates a compound that helps to alleviate non-alcoholic steatohepatitis (NASH), a disease that can lead to liver cirrhosis.