Urinary tract health remains a major concern in feline medicine, with calcium oxalate (CaOx) uroliths being particularly challenging to manage and prevent. Recent controlled studies have explored whether dietary potassium chloride (KCl) supplementation can safely increase water intake and urine output in cats, thereby diluting urinary minerals and reducing CaOx relative supersaturation (RSS). The results are promising and clinically relevant.

Study Designs

Three complementary studies were conducted in healthy adult cats:

• Study One: A two‑group comparison over 21 days, with control cats fed dry food containing 1.08% potassium (as fed) and treatment cats fed the same diet supplemented to 1.95% potassium.
• Study Two: A three‑group, dose–response, cross‑over trial. Cats received control food (0.84% potassium) or diets supplemented to 1.35% and 1.81% potassium, each for two weeks.
• Study Three: A two‑period cross‑over study, with cats alternating between control food and potassium‑supplemented food (1.95%) for two weeks per phase.

Key Findings

• Urine production: Cats consuming potassium‑supplemented diets consistently showed increased urine volume. In study one, urine output rose significantly (p = 0.037), while study three documented a 25% increase compared with controls.
• Water intake: Study two demonstrated a clear dose–response relationship—higher dietary potassium led to greater water consumption.
• Urine dilution: Specific gravity decreased across studies, reflecting improved dilution. Sodium and phosphorus concentrations were reduced accordingly.
• Mineral excretion: Potassium and chloride excretion increased, consistent with dietary intake.
• CaOx RSS: Importantly, study three showed a significant reduction in CaOx RSS (p = 0.007), indicating lower risk of stone formation.
• Safety: No adverse effects were observed in any of the trials, supporting the tolerability of potassium chloride supplementation up to 1.95% in dry food.

Clinical Implications

These findings suggest that moderate dietary potassium supplementation is a practical and safe strategy to enhance urine dilution in cats. By increasing water intake and urine volume, potassium chloride reduces urinary mineral concentrations and CaOx RSS—key factors in stone prevention. For clinicians, this offers a nutritional approach to complement other preventive measures such as encouraging hydration, managing dietary mineral content, and monitoring urinary pH.

Potassium chloride supplementation up to 1.95% (as fed) in feline dry diets appears safe and effective for reducing risk factors associated with calcium oxalate urolithiasis. While further long‑term studies in cats with a history of uroliths would be valuable, current evidence supports its use as a preventive nutritional strategy in healthy cats.