Helps dissolve and prevent pure struvite stones and helps prevent calcium oxalate stones

Lowers the risk of crystal and stone formation using RSS methodology for bladder health

Highly palatable hydrolyzed proteins help to reduce skin and GI reactions that may be a result of food sensitivities to common proteins found in pet food

Supports healthy digestion and reinforces the skin barrier with nutrients to support and maintain healthy skin

Whether this is your cat’s first urinary issue or she has developed food sensitivities and needs ongoing urinary care, your vet recommended Royal Canin Urinary SO + Hydrolyzed Protein for a reason. This veterinary-exclusive dry cat food was developed to nutritionally support your adult cat’s urinary tract and bladder health. It’s designed with Relative SuperSaturation (RSS) methodology to help lower ion concentration in urine, which contributes to stone formation. This formula promotes a urinary environment unfavorable to the formation of both struvite and calcium oxalate crystals. It also features highly digestible hydrolyzed protein, which helps reduce the risk of stomach and skin signs in cats with food sensitivities. Talk to your veterinarian about keeping your cat on this urinary cat food with Royal Canin Hydrolyzed Protein Treats for long-term urinary tract support.

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Discover our tool that calculates the daily portion for your pet. Fill in your pet's information and you will get their daily feeding recommendation. In case of weight issues, do not hesitate to consult your vet to adapt this portion. Note that this feeding recommendation is more precise than the feeding table, therefore the values may slightly differ.


Brewers rice, hydrolyzed soy protein, chicken fat, powdered cellulose, natural flavors, vegetable oil, dried chicory root, salt, fish oil, calcium sulfate, potassium chloride, sodium pyrophosphate, monocalcium phosphate, sodium silico aluminate, sodium bisulfate, calcium carbonate, DL-methionine, fructooligosaccharides, choline chloride, taurine, vitamins [DL-alpha tocopherol acetate (source of vitamin E), niacin supplement, D-calcium pantothenate, biotin, pyridoxine hydrochloride (vitamin B6), riboflavin supplement, thiamine mononitrate (vitamin B1), vitamin A acetate, vitamin B12 supplement, folic acid], trace minerals [zinc proteinate, zinc oxide, manganese proteinate, manganous oxide, copper sulfate, ferrous sulfate, sodium selenite, copper proteinate, calcium iodate], marigold extract (Tagetes erecta L.), rosemary extract, preserved with mixed tocopherols and citric acid.

Calorie Content

This diet contains 3628 kilocalories of metabolizable energy (ME) per kilogram or 334 kilocalories ME per cup on an as fed basis (calculated).

Nutrient Amount
Crude Protein (min)25.0%
Crude Fat (min)14.0%
Crude Fiber (max)6.9%
Moisture (max)8.0%
Calcium (max)0.9%
Phosphorus (max)0.9%
Magnesium (max)0.06%.
Cat Weight Low Activity Medium Activity High Activity
4.4 lb (2 kg) 1/4 cup (27 g) 3/8 cup (34 g) 3/8 cup (40 g)
6.6 lb (3 kg) 3/8 cup (36 g) 1/2 cup (45 g) 5/8 cup (54 g)
8.8 lb (4 kg) 1/2 cup (44 g) 5/8 cup (55 g) 3/4 cup (66 g)
11 lb (5 kg) 1/2 cup (51 g) 3/4 cup (64 g) 7/8 cup (77 g)
13.2 lb (6 kg) 5/8 cup (59 g) 3/4 cup (73 g) 1 cup (88 g)
Urinary SO + Hydrolyzed Protein Dry Cat Food

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Customer reviews

29 Sep 2021

Great product

Our vet recommended we switch to this from another brand and it's been very effective at curing the UTI issues we were having repeatedly. So glad we found it.
16 Jan 2021

Helped my cat so much

For the last two years I'd say my 5 year old male threw up a "hairball" at least once a month sometimes every day a week depending on the time of year. I thought it was normal especially when it was summer and he was shedding a lot. Then he had a urinary blockage scare a year ago. A few months after that I noticed he was scratching behind his ears so much he was almost bald. I was reading up about food allergies and once I switched him to this food he hasn't thrown up once (3 months now) and his hair is growing back. He's a very picky eater too so I'm so glad he likes it!
13 Jan 2021

Worked For My Boy!

My poor boy..back and forth the box suddenly one day..moaning in agony....Got to the vet. Dr Scheck (Hopewell Animal Hospital) prescribed this food after confirming bladder stones..within 4 more back and forth, no more agonizing cries...a peacful Bernie...I'm very thankful for this food. After another checkup...bladder stones DISSOLVED. He loved the food too. I'm very thankful for this food. Yes it was pricey, but it also saved me THOUSANDS of dollars on surgery to have the stones removed. Have used another of their Rx foods for my other cat in the past and it was great.
06 Oct 2020

My cat loves it!

When I adopted my cat, the foster said she vomited regularly. My vet recommended a hydrolyzed food. She also has one little kidney, so my vet suggested I try the so + hyrdolyzed and my kitty won’t eat anything else. She’s never vomited and her urine is perfectly concentrated and kidneys doing great. I also have a cat who had a bladder stone removed, as well as a cat with IBD. They can all eat the same food thanks to this stuff! I also feed the one who had the stone the so wet food and he loves it! Wouldn’t feed them anything else.
31 Oct 2019

No more crystals!!

I have had cats with struvite crystals which not only created major vet bills but also was extremely scary for myself and my furry family member. Urinary SO has been a ‘God send’. Haven’t had any scares in years since following this diet! I grateful to have piece of mind my felines are healthy and happy with many loving years to come! AND all gobble it up! Thank you Royal Canine! I added a photo from his birthday. Jaime loves his SO, the candle not so much.
mr caramel and mr simba
30 Oct 2019

Helps 2 problems in 1!

Both my cats love it and it helps sensitive tummies and urinary health.
29 Oct 2019

25 Oct 2019

Great for urinary crystals + food sensitivities

It's great that this food exists for cats with urinary crystals/feline idiopathic cystitis AND food allergies/sensitivities. Great product.
24 Oct 2019

all the cats like it

great choice by vet. was the only one he would eat
24 Oct 2019