The effects of synbiotic therapy on serum levels of microbiome-generated uraemic toxins have been assessed in a new study involving predialysis patients with chronic kidney disease (CKD). Data from the SYNERGY trial found that a 6 week prebiotic and probiotic therapeutic protocol favourably modified the stool microbiome in the 31 patients who completed the study, with enrichment of Bifidobacterium and depletion of Ruminococcaceae. Decreased serum levels of the toxin p-cresyl sulfate, but not indoxyl sulfate, were observed.