The use of probiotics in veterinary medicine has gained popularity in recent years and many different conditions are now successfully managed with probiotic therapy. The intestinal microflora and the impact of probiotics is currently an area of interest for researchers and clinicians alike. This article by James Kyffin, of Protexin Veterinary, will examine the variations in the microflora seen in specific conditions and how probiotics can influence this, with particular focus on the evidence available in dogs and cats.