Royal Canin Veterinary Diets Canine Urinary S/O Dry Dog Food (LP18) Indications: Bacterial cystitis Dissolution of struvite uroliths Struvite and calcium oxalate urolithiasis Key Benefits Struvite Dissolution - Urinary S/O Canine effectively dissolves struvite uroliths. An acidic urinary pH is unfavourable to the development of bacteria, which are frequently associated with struvite uroliths. Urine Dilution - Diluting urine decreases the urinary concentration of struvites and calcium oxalates. The larger urinary volume also ensures regular bladder wash-out. Low RSS - Undersaturated urine is an environment where crystals cannot proliferate. Thus the urine is unfavourable to the development of both struvite and calcium oxalate crystals. Low Magnesium - Magnesium is a component of struvite (magnesium ammonium phosphate) uroliths. Reduced level of magnesium, a natural component of struvite crystals.