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Guinea Pig Bladder Stone & Sludge (also known as Grit) seems to be a common condition in our pet guinea pigs. There are many things we can do to try and control this problem. Continue to read on for more information.

If a Guinea Pig is unable to Urinate this is a Medical EMERGENCY

And Must be admitted to a Vet Immediately

Bladder Stones (Known as Urinary Calculi or Uroliths) are hard stone-like structures, Usually composed of Calcium Carbonate. They normally form in the bladder.

Signs Of Stones

There are some signs that you can see physically with your Guinea Pig which could be a combination of any of the following :

Differential Diagnosis (Other Possible Conditions)

The following are other possible conditions that could be causing any of the above symptoms :-

What will my Vet do?

Your Vet will normally first examine you Guinea Pig by Palpate its lower abdomen. Stones can not always be found by Palpation.


Most Guinea Pigs can not pass stones on their own and require surgery to remove them.

Bladder Stones can sometimes be plucked out of the Urethra if close to the opening.

Occasionally a Guinea Pig can pass a stone before surgery so it is always best to complete an x-ray before surgery commences to locate its position.

If Bladder Stones enter in to the Urethra they are sometimes flush back in to the Bladder for removal. Normally two or more weeks of Antibiotics are prescribed to prevent infection while healing and will also treat most Urinary Tract Infections.

Multiple Stones Because New stones may reform within months or even weeks of surgery, it is important to monitor your pet after Stone Removal Surgery. Some pet owners have reported a recurrence of stones 2-3 weeks post surgery.


The cause of bladder stone formation is poorly understood. Because stones seem to run in families, it is likely there is strong genetic component. Frequent urinary tract infections have also been implicated, as well as improper diet, inadequate water intake and obesity.

Calcium Carbonate is the most common type of stone. Recent studies have shown that the Composition of the majority (90%>) of Urinary Stones is 100% Calcium Carbonate. A certain percentage also contain traces of Calcium Phosphate, Oxalate or Struvite.


A good quality diet is thought to help prevent the formation and reformation of Bladder Stones. Poor diets normally consist of Alfalfa pellets which contain High Levels of Calcium, some hays and vegetables may contribute to Stone formation.

A good diet would include :-

Grass Hay

Grass Hay should be the foundation of every Guinea Pigs Diet. Offer the best hay you can find to encourage eating as much as possible.


Guinea Pigs are Herbivores. Their digestive system is designed to extract nutrients from A variety of Grasses and Greens. Wet, Leafy Greens are a good choice.


Use a Low-Calcium Timothy Based Pellet and consider limiting or using no pellets at all. Some Timothy Guinea Pig Pellets have added calcium.

Vitamin D

Is required for absorption of  calcium. For a Guinea Pig that is not getting Regular exposure to Sun Light, removing pellets may result in a diet devoid of Vitamin D. Vitamin D is not present in Hays and Greens but is added to Guinea Pig Pellets. If you Plan on going Pellet Free you will need to consult your Vet for a supplement.


Take every opportunity to increase Fluid Intake.

If your Veterinarian has no experience of removing stones then please ask for a referral to A vet that has the experience.

Sammy’s Story

Below is an x-ray image of Sam taken in September 2012 showing a Small Stone and Sludge which was trapped in the Urethra (Tube leading to the Bladder from the  Kidney) which was removed within a week. Sam under went surgery for a bigger stone which took the whole of his bladder up. This was removed one month later. Around 4 weeks later Sam had another x-ray to find 4 small stones in the Urethra. He was put on 0.08ml Potassium Citrate from before his 1st surgery All attempts to stop the Calcium Stone formation failed. We kept Sam going until Mid November when he went of His Food/Drink. We rushed him to the vets and an ultrasound was performed and investigations found his Right Kidney had swollen and that it was possibly being caused by the the Kidneys not being able to flush properly. Sam was put to rest in November 2012 as we felt a 3rd Surgery was to much for him and that the inflamed Kidney may have already affected his other organs.

Click On Image For Larger View

Guinea Pig Bladder Stones Introduction