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My cat is on a new diet. How quickly can urinary crystals form?

Updated On September 23rd, 2025

Pet's info: Cat | American Shorthair | Male | neutered | 9 years and 4 months old | 13 lbs

I am going to be removing my 9 yr. old male cat from Hills Science Diet Urinary Tract food and putting him on Purina Pro Plan Urinary Tract Formula. He had a blockage 2 yrs ago that was "fixed" with fluids and antibiotics. How long does it normally take for crystals to form in the cat's system. I need an idea as to when to look for problems. Thank you

1 Answer

Most Helpful Answer

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Answered By Lauren Jones VMD

Veterinarian

Published on May 21st, 2017

Good for you for being so conscientious about Dusty's urinary health! Crystals can develop in a matter of days as the pH of the urine changes with a new diet. That said, some cats can develop crystals over a period of months to years. Since he has had urinary issues in the past, I would recommend asking your vet about checking a urinalysis after eating this new diet for one month. This will help to determine both if crystals are currently present and how the new diet is regulating the pH of his urine. Be sure to change his diet gradually over 5-7 days to decrease the risk of developing vomiting or diarrhea. I hope that all goes well!

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