A fact sheet: https://vetspecialists.co.uk/fact-sheets-post/probiotics-use-in-cats-and-dogs-fact-sheet/
Excerpts:
Improving the gut microflora may have more systemic effects as the intestinal microorganisms are thought to have a variety of roles, from digestion of nutrients and vitamins to production of beneficial compounds or regulation of the immune system. Although more studies are needed to assess the true effect of probiotics, some studies have suggested they may be beneficial for:
- Kidney function
- Liver function
- Allergic skin disease
- Gastro-intestinal signs following antibiotic treatment
- Constipation in cats
Of note, some of the studies only reported mild changes and specialists are still debating if the use of probiotics is clinically useful for some patients.
What are the risks in using probiotics/ prebiotics for my dog or cat?
Despite the fact that using probiotics/ prebiotics changes the flora and may have a more general influence on the rest of the body, there are currently no reported significant adverse effects in dogs and cats.