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The Vet Files: Why Is My Cat Suddenly Peeing on the Floor?

Reviewed by Dr. Bill Saxon DVM, DACVIM, DACVECC on Wednesday, April 22, 2015
Posted January 02, 2014 in Cat Diseases & Conditions A-Z

Dr. Phil Zeltzman is a traveling, board-certified surgeon in Allentown, PA. His website is He is the co-author of “Walk a Hound, Lose a Pound” (

Kelly Serfas, a Certified Veterinary Technician in Bethlehem, PA, contributed to this article.

A friend and cat lover recalls: "My cat, Catnip, peed on the floor! At first, I was so mad at him. I locked him up in the basement with his litter box, food and water. The urine looked a little red, but I was convinced he was fine since he was acting normally otherwise. [He was] Just being a bad boy [and] not using his litter box!"

Two days later, my friend woke up and noticed that Catnip had gone in and out of his litter box multiple times.  She assumed that he was either getting diarrhea, or that he was constipated--both assumptions are common but wrong.  Because she had to go to work, Catnip went back to the basement.

Ten hours later, when she got home from work, there was nothing in the litter box! She looked around the basement for Catnip and found him hiding under an old armchair. When she pulled him out, he wasn't fighting as he usually does.  He was clearly in pain.  He seemed quite depressed and cried a weaker meow than usual. I told her to rush Catnip to the emergency vet hospital where they confirmed my suspicion: Catnip was "blocked."

Blocked? As the emergency vet explained, male cats can have urine that forms crystals or debris which clumps together and can cause a blockage in the urethra (i.e. the narrow tube that leads urine out of the bladder). This can either partially or completely prevent male cats from urinating. 

A complete blockage is both painful and dangerous. It can cause a number of life threatening conditions, for example, if a cat (or a dog) cannot pee, their bladder gets very large, and becomes at risk of rupturing. There are also consequences for other organs including the kidneys and the heart.

At the clinic, Catnip was immediately given pain medications. Blood work showed abnormal kidney values, as well as an increased potassium level, which is toxic. He then received sedation and was "unblocked" with a tiny urinary catheter. Catnip stayed at the vet hospital overnight on IV fluids and pain medications.

When the vet called the next morning, he said Catnip

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Dr. Phil Zeltzman is a board-certified veterinary surgeon and author. His traveling practice takes him all over Eastern Pennsylvania and Western New Jersey. You can visit his website at, and follow him at