My cat keeps urinating outside the litter box. What could be wrong?
Reviewed by Dr. Ashim Sarkar
BVSc & AH · Licensed Veterinarian · Omelo Vet
Inappropriate elimination is one of the top reasons cats see vets and is also the leading cause of cats being surrendered to shelters. It's critical to distinguish between a medical and a behavioural cause, because the treatment is completely different.
Medical causes - rule these out first
- **Urinary tract infection (UTI)**: Painful urination causes cats to associate the litter box with pain, so they try urinating elsewhere hoping it will hurt less - **Feline idiopathic cystitis (FIC)**: The most common cause in cats under 10 - bladder wall inflammation linked to stress - **Bladder stones or urethral plugs**: Cause straining and frequent small urinations; a blocked urethra in male cats is a life-threatening emergency - **Diabetes or kidney disease**: Increased urination can overwhelm litter box capacity or cause urgency - **Arthritis**: An older cat may avoid the litter box because it's painful to climb in
Behavioural causes
- Box cleanliness: Most cats require the box to be scooped at least daily - Box size: Many commercial boxes are too small - the box should be 1.5x the length of your cat - Litter type: Unscented, fine-grain clumping litter is preferred by most cats - Location: Isolated, quiet locations are preferred; never place the box near food and water - Insufficient boxes: The rule is one box per cat plus one extra - Stress: New pets, new people, changes in routine
What to do
Book a vet appointment and bring a fresh urine sample if possible. A urinalysis and urine culture will rule out infection. Imaging may be needed if bladder stones are suspected.
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