I normally order Pro-Kolin probiotic for my dogs (i think they are good for the cats too). My Vet recommended pro-kolin few years ago and since than i do a 10 days course for them once in 6 months. Sometimes its not easy to get them, i mostly do my purchases from the Pet pharmacy or Amazon. The only one thing with Amazon that there is a limit of pieces you can order (last time it was 3 if i remember that right) and if i want to buy probiotics for the whole course it is not enough.