Green urine in cats is not normal and almost always signals something that needs veterinary attention. The most common causes include urinary tract infections with certain bacteria, reactions to medications, or a buildup of bile pigments from liver problems. While some causes are benign and temporary, others point to serious illness, so getting your cat examined promptly is important.
Bacterial Urinary Tract Infections
One of the most recognized causes of green-tinted urine is a urinary tract infection caused by Pseudomonas bacteria. This particular type of bacteria produces pigments as it grows, and those pigments can turn urine green or blue-green. A standard urine culture at the vet’s office will confirm whether Pseudomonas or another organism is present. If your cat’s green urine is accompanied by straining in the litter box, frequent small urinations, crying while peeing, or licking around the genital area, an infection is a strong possibility.
Liver and Bile Pigment Problems
Your cat’s body breaks down old red blood cells through a process that produces pigments called bilirubin and biliverdin. Biliverdin is naturally green. Normally, the liver processes these pigments efficiently and they don’t accumulate in urine. But when the liver isn’t functioning properly, or when red blood cells are being destroyed faster than usual, excess pigment can spill into the urine and tint it green.
Liver disease, bile duct obstruction, and conditions that cause rapid red blood cell destruction (hemolytic anemia) can all push these pigments into the urine. A basic urinalysis will often show elevated bilirubin on a dipstick test. Your vet may follow up with blood work, including a complete blood count and liver enzyme panel, to pinpoint the underlying problem. In rare cases, a genetic defect in how the body processes these pigments can cause persistent green urine, though this has been documented more in dogs than cats.
Medications and Anesthesia
If your cat recently had surgery or a veterinary procedure, the anesthesia drug propofol can cause green urine. This happens when the liver can’t keep up with processing the drug’s byproducts, and the body eliminates them through the kidneys instead. The green color typically appears within hours of the procedure and resolves on its own within about 12 hours, though it can occasionally last up to two days. It’s a rare side effect (occurring in fewer than 1% of cases) and is considered harmless.
Methylene blue, a compound historically included in some urinary tract medications for cats, is another known cause. It directly stains urine blue to green. However, methylene blue has largely fallen out of favor in feline medicine because it can trigger severe hemolytic anemia in cats, sometimes within three to four days of use. If your cat was given any medication containing methylene blue and you notice green urine along with lethargy or pale gums, that combination warrants urgent care.
Food Dyes and Other Ingested Substances
Cats that eat something containing artificial green or blue dye can pass green-tinted urine. This is more common than you might expect if your cat gets into human food, certain treats, or drinks water from a source treated with dye (like a toilet bowl with a blue cleaning tablet). If dye ingestion is the cause, the color change is temporary and clears once the substance passes through the system, usually within a day or two.
When Green Urine Is an Emergency
Green urine on its own warrants a vet visit, but certain accompanying signs turn it into an emergency. If your cat is straining repeatedly in the litter box and producing little or no urine, this could indicate a urethral blockage. A blocked cat can develop kidney failure, dangerous electrolyte imbalances, and death in less than 24 to 48 hours without treatment. Male cats are especially prone to blockages because of their narrower urethra.
Other red flags to watch for alongside green urine include vomiting, complete loss of appetite, visible distress or vocalization, and a swollen or painful abdomen. Any of these combinations means your cat needs to be seen immediately, not at the next available appointment.
What Your Vet Will Do
The first step is a urinalysis, which checks the urine’s color, concentration, pH, and the presence of bacteria, blood, protein, or bile pigments. A urine culture can identify the specific bacteria involved if infection is suspected. Most vets will also run blood work to evaluate liver function, kidney values, and red blood cell counts. Abdominal imaging with ultrasound or X-rays may be recommended if the vet suspects a blockage, bladder stones, or a liver issue.
Treatment depends entirely on the cause. A bacterial infection calls for antibiotics targeted to the specific organism. Liver disease requires its own workup and management plan. Medication-related color changes simply resolve once the drug clears your cat’s system. The key takeaway is that green urine is your cat’s body flagging something abnormal, and identifying the cause early gives you the best range of treatment options.