To improve the treatment of children with irritable bowel syndrome (IBS), investigators have developed a sophisticated way to analyze the microbial and metabolic contents of the gut. A report describes how a new battery of tests enables researchers to distinguish patients with IBS from healthy children and identifies correlations between certain microbes and metabolites with abdominal pain. With this information, doctors envision tailoring nutritional and targeted therapies that address a child’s specific gastrointestinal problems.