CONDITION

Cholelithiasis

Cholelithiasis refers to the formation of stones within the gallbladder, a small organ that stores bile produced by the liver. These stones form when components of bile—such as cholesterol, bilirubin, or calcium salts—crystallise and accumulate over time. In dogs and cats, gallstones may exist without causing any outward signs, or they may contribute to episodes of abdominal discomfort, vomiting, jaundice, or changes in appetite and behaviour. Many owners first encounter this term after an ultrasound scan performed for another reason reveals stones incidentally, or when their pet develops signs that prompt investigation of the liver and biliary system. The clinical picture varies considerably depending on whether a stone remains static in the gallbladder or moves into a bile duct, and whether inflammation or obstruction develops as a result. This page explores the patterns that can bring cholelithiasis to light, the mechanisms underlying stone formation, the imaging and laboratory tools used to confirm and characterise the condition, and the range of approaches—from monitoring to surgical intervention—that may be considered depending on the individual animal's circumstances.

Why this matters now

Cholelithiasis tends to be identified more often in middle-aged to older dogs and cats, though stones may begin forming years before any signs appear. Certain breeds, including Shetland Sheepdogs, Miniature Schnauzers, and some terrier breeds, appear more frequently in clinical reports, suggesting an inherited component to bile composition or gallbladder function. In cats, stone formation is less common overall but may be associated with concurrent liver or pancreatic conditions. Dietary factors, chronic inflammation of the bile ducts, and disturbances in bile flow can all influence the likelihood of stone development over time.

Many animals carry gallstones for months or years without detectable signs, and some will never develop symptoms. When progression does occur, it often follows a gradual pattern: a stone may grow slowly within the gallbladder, or a smaller fragment may shift position and partially obstruct a bile duct. The timeline from stone formation to clinical signs varies widely between individuals, influenced by stone size, location, and the presence of concurrent inflammation or infection. In a minority of cases, obstruction or rupture of the gallbladder can develop over hours to days, though this represents a distinct shift in the condition's usual tempo.

Signals & patterns

Early signals

Intermittent reduced appetite

An owner may notice their dog or cat eating less enthusiastically for a day or two, then returning to normal. This pattern can recur over weeks or months, often without other obvious signs. It may reflect transient discomfort or mild nausea related to fluctuating bile flow.

Occasional vomiting

Vomiting may occur sporadically, sometimes containing bile or foam, and often without a clear trigger such as dietary change. The episodes tend to be separated by days or weeks of normal behaviour. This can reflect irritation of the stomach or upper intestine when bile movement is disrupted.

Quiet discomfort after eating

Some animals become subdued or restless in the hour or two following a meal, shifting position frequently or seeking out cool surfaces. This may indicate mild abdominal discomfort as the gallbladder contracts to release bile in response to food entering the digestive tract.

Subtle abdominal guarding

An owner may notice their pet flinches slightly when the right side of the abdomen is touched, or shifts away during handling. This guarding can be inconsistent and easily missed, as many animals tolerate gentle palpation without overt reaction.

Later signals

Yellowing of gums and eye whites

A yellow or orange tint may become visible in the mucous membranes of the mouth and the sclera of the eyes, indicating a build-up of bilirubin in the bloodstream. This typically occurs when a stone obstructs bile flow more completely, preventing pigment from being excreted normally into the intestine.

Persistent lethargy and withdrawal

The animal may spend more time resting, show little interest in play or interaction, and move with less energy than usual. This shift in behaviour can reflect systemic effects of bile duct obstruction, inflammation, or infection spreading from the gallbladder.

Pale or clay-coloured stools

Faeces may lose their normal brown colour and appear grey, tan, or putty-like, a change that occurs when bile pigments are no longer reaching the intestine. This is often noticed alongside darkening of the urine, which may take on a strong yellow or amber hue.

Marked abdominal pain

The animal may adopt a hunched posture, vocalise when touched, or resist lying down in certain positions. This level of discomfort can indicate more severe inflammation, gallbladder distension, or secondary infection, and represents a notable escalation from earlier, milder patterns.

Click to read about the biological mechanisms

How this is usually investigated

Investigation typically begins with a review of the pattern and duration of signs, alongside a physical examination to identify tenderness in the cranial abdomen or yellowing of mucous membranes. Blood tests often follow, looking for markers of bile duct obstruction or liver inflammation. Imaging is then used to visualise the gallbladder and bile ducts directly, and in some cases, additional sampling or advanced imaging helps clarify the composition and extent of disease.

Physical examination

Purpose: The veterinary surgeon palpates the abdomen, feeling for discomfort in the area beneath the ribcage on the right side, and examines the gums and sclera for jaundice. This provides an initial sense of whether bile flow may be impaired.
Considerations: Many animals with gallstones show no abdominal tenderness, and jaundice may be absent if obstruction is incomplete or intermittent. The examination guides the need for further testing but cannot confirm the presence or location of stones.

Blood biochemistry

Purpose: Liver enzyme activity and bilirubin concentration are measured to detect evidence of bile duct obstruction or inflammation. Elevations in alkaline phosphatase, gamma-glutamyl transferase, and bilirubin can suggest impaired bile flow, while changes in other parameters may point to concurrent liver or pancreatic involvement.
Considerations: Blood results reflect the functional impact of obstruction rather than the stones themselves, and enzyme patterns can overlap with other hepatobiliary conditions. Normal results do not exclude gallstones, particularly if they remain within the gallbladder without obstructing outflow.

Abdominal ultrasonography

Purpose: Ultrasound allows direct visualisation of the gallbladder, revealing the presence, size, and number of stones, as well as thickening of the gallbladder wall or dilation of the bile ducts. It can also identify sludge—a semi-solid suspension of bile components—that may precede stone formation.
Considerations: The quality of ultrasound imaging depends on the operator's experience and the animal's body condition, and very small stones or those within the bile ducts can be difficult to detect. Gas in overlying bowel loops may obscure portions of the image.

Radiography

Purpose: Plain radiographs of the abdomen may reveal gallstones if they contain sufficient calcium to appear radio-opaque. This is more common in certain stone types, particularly those composed of calcium carbonate or calcium bilirubinate.
Considerations: Many gallstones are radiolucent and invisible on standard radiographs, so a negative result does not rule out cholelithiasis. Radiography is often used as a screening tool or when ultrasound is not readily available.

Bile culture and cytology

Purpose: If surgery or fine-needle aspiration is undertaken, bile can be sampled for bacterial culture and microscopic examination. This identifies concurrent infection and informs decisions about antimicrobial use.
Considerations: Sampling carries a small risk of bile leakage or peritonitis, so it is typically reserved for cases where surgery is already planned or where infection is strongly suspected. Not all animals with gallstones have infected bile.

Options & trade-offs

Management is shaped by the presence and severity of signs, the location and size of stones, and the individual animal's overall health. Some animals are monitored over time with periodic imaging and blood tests, while others undergo surgical removal of the gallbladder or stones. Nutritional adjustments and treatment of concurrent conditions may form part of the overall approach, and many cases involve a combination of methods tailored to what the owner and veterinary team find practical and tolerable.

Monitoring with serial imaging

Animals with incidentally discovered gallstones and no clinical signs may be observed over months to years, with repeat ultrasound examinations and blood biochemistry at intervals to detect any change in stone size, gallbladder wall thickness, or liver enzyme activity. This allows early recognition of progression without immediate intervention.

Trade-offs: Monitoring requires commitment to regular visits and the acceptance that stones may remain indefinitely without causing harm. It does not remove the stones, and a shift to symptomatic disease can occur between scheduled checks.

Cholecystectomy

Surgical removal of the gallbladder eliminates the stones and the organ in which they formed, and is often considered when obstruction, infection, or gallbladder wall rupture is present or anticipated. The procedure is performed under general anaesthesia and involves ligation of the cystic duct and artery, followed by excision of the gallbladder. Bile flow continues directly from the liver into the common bile duct after surgery.

Trade-offs: Surgery carries the risks associated with anaesthesia and abdominal exploration, including bleeding, bile leakage, and infection. Recovery typically spans one to two weeks, and some animals require ongoing dietary management or monitoring of liver function. It is less suitable for animals with significant concurrent illness or poor anaesthetic candidacy.

Dietary modification

Feeding a diet lower in fat and moderate in protein may reduce gallbladder workload and bile secretion, potentially slowing further stone formation or sludge accumulation. Some diets are formulated to support hepatobiliary health and may be used alongside other interventions.

Trade-offs: Dietary change alone does not dissolve existing stones or reverse obstruction, and its impact on stone progression in dogs and cats is not well quantified. Palatability and individual tolerance vary, and some animals may require trial and adjustment of formulations.

Antimicrobial therapy

If bile culture identifies bacterial infection, antimicrobials selected on the basis of sensitivity testing may be administered to reduce inflammation and the bacterial load within the biliary tree. This is often used in combination with surgical or supportive measures.

Trade-offs: Antimicrobials do not remove stones and are unlikely to resolve obstruction on their own. Their use is guided by culture results where available, and prolonged courses may be needed if infection is entrenched or if drainage remains impaired.

Ursodeoxycholic acid

This bile acid can be given orally to alter bile composition, increase bile flow, and reduce the lithogenic potential of bile in some cases. It may be used in animals with sludge or small stones where surgery is deferred, or as an adjunct after cholecystectomy.

Trade-offs: Evidence for dissolution of established gallstones in dogs and cats is limited, and response varies between individuals. It is generally well tolerated but requires weeks to months of administration, and its role is more supportive than curative in most scenarios.

Common misconceptions

Misconception:

"Gallstones in dogs and cats can be dissolved with medication in the same way bladder stones sometimes are."

Reality:

Unlike some types of urinary stone, gallstones in small animals are rarely amenable to medical dissolution. The composition and setting differ, and bile acids or other agents may slow progression or support bile flow but do not reliably break down existing stones. Surgical removal remains the only certain means of eliminating gallstones once they have formed.

Misconception:

"If a dog or cat has gallstones but no symptoms, they will inevitably develop serious problems later."

Reality:

Many animals live out their natural lifespan with incidental gallstones that never cause obstruction, infection, or discomfort. The likelihood of progression to symptomatic disease varies, and regular monitoring allows early detection of change if it occurs. Not all gallstones behave the same way, and clinical outcomes span a wide spectrum.

Misconception:

"A low-fat diet will dissolve gallstones that have already formed."

Reality:

Dietary modification can reduce the workload on the gallbladder and may influence the formation of new sludge or stones, but it does not dissolve existing solid stones. Its role is more about managing concurrent conditions and supporting overall hepatobiliary health than reversing established cholelithiasis.

Understanding how cholelithiasis relates to other hepatobiliary conditions—such as cholecystitis, pancreatitis, or chronic hepatitis—can help place any observations into a broader metabolic picture. The metabolic health pillar explores how bile flow, liver function, and inflammatory processes interact over time. For animals undergoing monitoring or surgery, the question of what follow-up imaging or blood work may look like in the months ahead is often a useful part of ongoing conversations.

Last reviewed: 31 July 2026 · Dr Alastair Greenway MRCVS