Green urine is almost always harmless, usually caused by something you ate, drank, or a medication you’re taking. In most cases, the color returns to normal within a day or two once the cause passes through your system. That said, there are a small number of situations where green urine can signal an infection or a liver problem worth checking out.
Food Dyes and Artificial Colors
The most common reason for green pee is water-soluble artificial dyes in food and drinks. Brightly colored sports drinks, green beer on St. Patrick’s Day, popsicles, cake frosting, and candies can all tint your urine green. The dyes pass through your digestive system, get filtered by your kidneys, and show up in the toilet bowl. This is completely harmless and typically clears up within one to two bathroom trips after you stop consuming the dyed food or drink.
Supplements and Chlorophyll
If you take chlorophyll or chlorophyllin supplements (popular for detoxing or reducing body odor), expect green urine. Oral copper chlorophyllin at doses of 100 to 200 mg per day has been documented to discolor urine green. The same goes for “greens” powders and liquid chlorophyll drops that have become trendy in recent years. B vitamins, particularly B2 (riboflavin), are more famous for turning urine bright yellow, but when that intense yellow mixes with naturally occurring blue-tinted pigments, the result can look yellowish-green.
Medications That Turn Urine Green
A surprisingly long list of medications can cause green urine. Several of these contain chemical groups called phenols, which the liver processes and the kidneys excrete as green-tinted compounds. These include promethazine (an anti-nausea drug), cimetidine (a heartburn medication), and propofol (the anesthetic commonly used during surgeries and procedures). If you’ve recently had a procedure under sedation and notice green urine afterward, propofol is the likely explanation.
Other drugs that cause green urine through different mechanisms include amitriptyline (a tricyclic antidepressant), indomethacin (an anti-inflammatory pain reliever), and metoclopramide (used for nausea and gastroparesis). Methylene blue, a dye used in certain urinary tract medications, is another well-known culprit. If you started a new medication recently and your urine changed color, check the drug’s side-effect information or ask your pharmacist.
Urinary Tract Infections
Certain bacteria that infect the urinary tract produce pigments that turn urine green. Pseudomonas aeruginosa is the most commonly cited species. This type of infection is more common in people with catheters or those in hospital settings, but it can happen to anyone. Unlike dye-related color changes, a bacterial infection will usually come with other symptoms: burning or pain when you pee, needing to urinate more frequently, lower abdominal discomfort, or urine that smells unusually strong or fishy. Fever and chills point toward a more serious infection that may have reached the kidneys.
Liver and Bile Problems
In rare cases, green urine relates to how your liver processes bile. Your body normally breaks down old red blood cells into a green pigment called biliverdin, which is then quickly converted into the yellow pigment bilirubin. When the liver is severely damaged, as in advanced cirrhosis or liver cancer, biliverdin can build up and spill into the urine, turning it green. This condition, called hyperbiliverdinaemia, is uncommon and typically occurs alongside obvious signs of serious liver disease: yellowing of the skin and eyes (which may take on a greenish tint), swelling in the abdomen, and significant fatigue. Green urine from liver disease is not something that shows up in isolation.
Rare Causes in Children
A genetic condition called familial benign hypercalcemia can cause blue or blue-green urine in infants and young children. Sometimes referred to informally as “blue diaper syndrome,” this is an inherited condition related to how the body handles calcium. It’s rare and is usually identified early in life, not something that appears for the first time in adults.
How to Tell If It’s Serious
Start with the simplest explanation. Think back over the last 24 hours: did you eat or drink anything with bright food coloring? Did you start a new medication or supplement? If so, wait a day or two and see if the color returns to its usual pale-to-medium yellow. Dye-related green urine resolves quickly once the substance clears your system.
Pay attention to what else is happening alongside the color change. Green urine on its own, with no other symptoms, is rarely a problem. But if you also notice pain when urinating, abdominal pain, pain in your mid-back, fever, chills, or a strong and persistent odor lasting more than a couple of days, those are signs that something beyond food coloring is going on and worth getting checked out. The combination of unusual color plus any of those symptoms is what separates a harmless curiosity from a potential health issue.