Royal Canin Veterinary Diet Urinary S/O Cans will help your dog achieve and maintain top-notch urinary health. The Royal Canin Vet Diet Urinary S/O formula does everything it can to discourage crystals from forming. Not only does it work to dissolve struvite stones that are already present, but its low levels of magnesium helps to limit the chance of new ones growing. It also dilutes the urine, which helps to reduce the risk of crystals forming. Product details Wet-food formula for urinary health in dogs for dogs with bacterial cystitis, or with recurrent struvite and calcium oxalate urolithiasis not suitable for dogs with chronic renal failure, metabolic acidosis, heart failure, pancreatitis (or history of pancreatitis), or hyperlipidaemia do not feed to pregnant or lactating dogs dissolves struvite stones discourages formation of new crystals use in consultation with a veterinarian.