Chronic diarrhoea can be frustrating to treat- for owners and vets alike. A logical and practical approach to cases is important to quickly establish which cases need investigation and which can have therapeutic trials. For those animals that need investigation, a stepwise progression through non-invasive (laboratory-based) testing through to more invasive (biopsy) testing is indicated. Decision making about when these diagnostics should occur is vital to maximise chances of successful outcomes. The mainstay of therapeutic trials in clinically well animals with chronic diarrhoea is currently manipulation of the microbiome- which can be done in a variety of ways: prebiotics, probiotics, antibiotics or faecal microbial transplantations. This talk will demystify some of the confusion around prebiotics and probiotics and hopefully encourage practitioners to avoid the use of antibiotics in most cases of chronic diarrhoea.