Purina Pro Plan Veterinary Diets UR Urinary St/Ox Feline Formulas are made with high-quality ingredients and formulated to help reduce the risk of urinary stone formation. The science behind our therapeutic diets represents a collaboration between Purina nutritionists, researchers and veterinarians. Promotes a urinary environment unfavorable to the development of struvite and calcium oxalate crystals Helps dissolve struvite stones Helps reduce the risk of both struvite and calcium oxalate stone recurrence Promotes increased urine volume to dilute the urine UR St/Ox canned diets contain significant moisture, contributing to total water intake Moderate fat content Great taste