Description:The pathogenesis of ME/CFS, a disease characterized by unexplained debilitating fatigue, cognitive dysfunction, sleep disturbances, orthostatic intolerance, fever, lymphadenopathy and irritable bowel syndrome (IBS), is poorly understood. There are no validated diagnostic tests or interventions to mitigate disease. Here we report association modeling, biomarker discovery, biochemical enrichment analysis and topological network visualization of plasma metabolomic, fecal bacterial metagenomic and clinical data from 50 ME/CFS patients and 50 healthy controls.