Why is my cat straining in the litter box? Causes, when to worry, and what to do tonight.

Straining in the litter tray almost always means one of three things: a UTI, cystitis (FIC), or — most urgently — a urethral blockage. The difference between them is the difference between a £60 vet visit and a £2,000 emergency.

Step 1: Is your cat producing any urine at all?

Watch one or two visits to the tray. If your cat squats and produces a normal-sized puddle, the situation is uncomfortable but not immediately critical — book a vet appointment for the next day. If your cat squats repeatedly and produces nothing, very little, or just a few drops, treat this as an emergency. In a male cat, this is a urethral blockage until proven otherwise.

Common causes of a cat straining to urinate

• Urinary tract infection (UTI) — bacterial, painful, treatable with antibiotics if caught early.

• Feline idiopathic cystitis (FIC) — stress-related bladder inflammation, the most common UK cause.

• Bladder stones or crystals — physical obstruction, often requires diet change and sometimes surgery.

• Urethral blockage — life-threatening, male cats especially. Hours, not days.

• Constipation — your cat may be straining to defecate, not urinate. Look at output.

What to do tonight

Call your vet — daytime practice if it's open, out-of-hours service if not. Describe exactly what you're seeing: how often, how much output, whether your cat is male or female, any vocalising, any blood. Don't try to wait it out. Cats with urinary issues do not improve overnight.

How to know it's coming next time

The cheapest way to never be in this situation again is to monitor litter chemistry daily. Kittydoctor's colour-changing crystals show pH shifts and blood traces 3–7 days before straining behaviour starts. Most of our customers tell us the same story: "I caught it before he ever cried."