Royal Canin Veterinary Diet Urinary SO is a prescription dog food made to help dissolve struvite bladder stones and lower the chance of new struvite or calcium oxalate stones forming. It is sold through veterinarians, and it only makes sense after a vet has diagnosed what kind of crystals or stones your dog has. Feeding it without a diagnosis can be useless or even harmful.
How Urinary SO Works
The diet changes the chemistry of your dog’s urine so stones are less likely to form and, for struvite, easier to dissolve.
- More urine: The recipe encourages drinking and produces more dilute urine, which flushes out minerals.
- Lower magnesium: Struvite stones are made of magnesium ammonium phosphate, so the food limits those minerals.
- Controlled urine acidity: The diet keeps urine in a range that is unfavorable to crystals.
- Lower ion concentration: Royal Canin uses a measure called relative supersaturation (RSS) to describe how likely urine is to form crystals, and designs the food to reduce it.
Royal Canin says the diet is for adult dogs. According to the company’s product page, vets typically feed it for about 5 to 12 weeks to dissolve struvite stones and for up to about 6 months to lower the risk of struvite coming back. Your vet sets the exact plan.
Dry or Canned
Urinary SO is sold in dry and canned forms. Canned food adds water, which can help dilute urine. Ask your vet which form suits your dog, and whether the two can be mixed.
Things to Know Before You Start
- It needs a vet’s authorization. It is a therapeutic diet, so you will need a prescription.
- It is not for every stone type. Calcium oxalate stones do not dissolve with food, and some stones need surgery or other treatment.
- It is not for puppies or pregnant dogs. The recipe is made for adult dogs.
- It is more expensive than regular food. Ask your vet how long your dog will need it.
- Do not add treats or table scraps. Extras can undo the diet.
Signs of a Urinary Problem
Call your vet if your dog strains to urinate, urinates often in small amounts, has blood in the urine or licks the genital area. A dog that cannot pass urine is an emergency, especially a male dog.
Tips for Success
- Encourage water by keeping bowls fresh and adding water to meals.
- Offer frequent bathroom breaks.
- Switch foods gradually unless your vet says otherwise.
- Schedule recheck urine tests and X-rays as your vet advises.
For other vet-directed diets, see our reviews of Royal Canin Renal and Hill’s Digestive Care, and our guide to treats for dogs with kidney disease.
This is general information, not veterinary advice. Only feed a prescription diet under your veterinarian’s direction.
Bottom Line
Urinary SO is a useful tool for dogs with struvite stones, but it works only when it is matched to a diagnosis and fed exactly as your vet directs.
