Cranberry has a reputation for preventing urinary tract infections in women, but does it also work for dogs and cats? The short answer is “maybe.” Cranberry extracts can prevent bacteria from sticking to the bladder wall, which does seem to stop some infections from developing. Cranberry has also been used to treat active bladder infections, but the evidence that this is effective is not very convincing.
If your pet has recurrent urinary tract infections and you are looking for something that might prevent or at least delay the appearance of the next one, trying a nutritional supplement that contains cranberry makes sense. Make sure you know what you are giving your dog or cat, however. Supplements often contain multiple ingredients, some of which could actually make your pet’s condition worse rather than better. For example, cranberry is sometimes combined with potassium citrate, which raises the pH of urine. Such urinary alkalanizers do help prevent recurrences of calcium oxalate bladder stones, but if your dog or cat has a history of struvite stones, they could actually increase the chances that the stones will come back.