Bladder Stones in Guinea Pigs

What are bladder stones?

Uroliths (bladder stones) are mineral structures that form in the bladder.  These uroliths can remain in the bladder or get stuck in the urethra during urination. Sometimes small stones can pass as the guinea pig urinates but more often they cause a problem that can be life threatening. Uroliths can cause irritation to the bladder wall, bloody urine, or can completely block the urethra.

Bladder sludge is defined as gritty particles that accumulate in the bladder and often can lead to the formation of stones.

It is not completely understood what causes bladder stones. There is evidence that suggests there is a genetic predisposition towards the development of stones. Almost all of guinea pig uroliths are composed of calcium carbonate.


  • Bloody or pink tinged urine
  • Squeaking while urinating or defecating
  • Gritty residue remaining after urine dries
  • No urine production
  • Decreased activity

If you notice any of these symptoms it is important to call your exotic veterinarian. Bladder stones not preventing urination is life threatening.


An x-ray or ultrasound done by a veterinarian can confirm bladder stones. If stones are present, a surgical procedure known as a cystotomy is often recommended to remove them. A stone analysis can be done to determine the composition and further help to prevent future development.

Diet is important to take into consideration in preventing stones. A high calcium intake can increase the likeliness of stone formation. A good quality diet including unlimited hay, variety of vegetables (leafy greens), and limited low-calcium timothy pellets. Poor diets such as alfalfa pellets and low grasses and greens can contribute to stone formation or reformation.

Fruits such as raisins, oranges and blackberries have high calcium content and should be avoided.

Increasing fluid intake by wetting down leafy greens or adding another water bottle to encourage water consumption can help in the prevention of stones.

A table of calcium content for vegetables and fruits is available on GuineaLynx.

Lisa Karr-Lilienthal, Ph.D., and Belle Flores – University of Nebraska-Lincoln