Best Probiotics for Women, Men, Dogs and Cats. Understanding Pre- and Probiotics for Dogs, Cats, and People. You know I'm a big believer in reading the ingredient labels in all our pets' products, but when I turn over a box or jar of probiotics, I'm totally confused. I'm not a microbiologist! So I asked some experts in the field of microbiology and pet health for help in understanding probiotics for pets and ourselves