New research using germ-free mice demonstrates a causative role of gut microbiota in fibromyalgia-like chronic pain. Transferring fecal samples from fibromyalgia patients induced systemic pain sensitivity and behavioral signs of discomfort in mice, while microbiota from healthy donors alleviated symptoms. This provides pivotal experimental support for the microbiome’s contribution to fibromyalgia pathology, a chronic pain syndrome lacking clear tissue damage. The findings, led by McGill University and Israel Institute of Technology teams and published in Neuron, open potential avenues for microbiome-targeted therapies in fibromyalgia management.