Why your cat stopped using the litter box

A cat who was reliable and now isn't is telling you something. The order in which you investigate matters, because the first category is the urgent one.

First: rule out medical causes

Urinary tract infection, crystals, bladder stones, kidney disease, diabetes, arthritis making the box hard to climb into, and in older cats, cognitive change — all present as "stopped using the box".

A male cat straining without producing urine is an emergency. Blockage kills within a day or two. Do not spend that day rearranging litter trays.

Book a vet visit with a urine sample before you change anything else.

Second: the box itself

Cats are specific, and most litter box setups are built for human convenience.

• Number. One tray per cat, plus one spare. Two cats need three trays.
• Size. The tray should be about one and a half times the cat's length. Most commercial trays are too small.
• Cover. Many cats dislike hoods — they trap smell and remove escape routes. Try uncovered.
• Litter. Unscented, fine-grained clumping suits most cats. Scented litter is marketed to people, not cats.
• Depth. Three to four centimetres. Deeper isn't better.
• Cleanliness. Scoop at least daily. A cat's threshold for a dirty tray is considerably lower than yours.

Third: location

Quiet, accessible, with more than one way out. Not beside a washing machine that starts without warning, not next to the food bowls, and not somewhere a dog or another cat can corner them. For senior cats, a tray on each floor, with a low entry side.

Fourth: stress

New pet, new baby, moved furniture, a neighbourhood cat visible through a window, building work. Cats mark and avoid when they feel their territory is uncertain. Pheromone diffusers, more vertical space, and restoring predictable routines all help.

Cleaning up properly

Use an enzymatic cleaner. Ammonia-based cleaners smell like urine to a cat and actively invite a repeat. Never punish — it reliably makes the problem worse, because it adds anxiety to a situation that is often caused by anxiety.