Green urine is almost always caused by something you ate, drank, or took as a medication or supplement. It looks alarming, but in most cases it’s completely harmless and clears up on its own within a day or two. The rare exceptions involve infections or liver problems, which come with other noticeable symptoms beyond just the color change.
Food Dyes and Diet
The most common reason for green urine is artificial food dye. Brightly colored dyes, especially blue and green ones found in candy, sports drinks, popsicles, cake frosting, and processed snacks, pass through your kidneys largely intact. Blue dye mixed with the natural yellow of urine produces a vivid green. You might not even remember eating something with dye in it, since it shows up in products you wouldn’t expect, like certain cereals, sauces, and ice cream.
Foods naturally high in chlorophyll, the pigment that makes plants green, can also tint your urine. Asparagus is the most well-known culprit, but large amounts of spinach, wheatgrass, or matcha could do it too. If you recently started juicing or added a lot of leafy greens to your diet, that’s a likely explanation. The color change from food typically resolves within one to two urinations once the pigment clears your system.
Supplements and Vitamins
Chlorophyll supplements, which have become popular for detox and skin health claims, are a frequent cause. Liquid chlorophyll in particular can turn urine noticeably green, sometimes within hours of taking it. If you recently started a chlorophyll supplement, that’s almost certainly your answer.
B vitamins, commonly found in multivitamins, are another source. B vitamins are water-soluble, meaning your body excretes whatever it doesn’t need through urine. While B2 (riboflavin) is famous for turning urine bright yellow, certain B vitamin combinations in multivitamins can shift the color toward green. This is harmless and simply means your body is flushing out the excess.
Medications That Change Urine Color
Several prescription and over-the-counter medications can turn urine green. Some of the more common ones include:
- Propofol: a sedative used during surgery. Green urine after a procedure is well-documented and typically resolves within 24 hours of the drug being stopped.
- Indomethacin: an anti-inflammatory used for gout and arthritis.
- Amitriptyline: a tricyclic antidepressant.
- Methylene blue: used to treat certain blood disorders and sometimes included in urinary tract medications.
- Sildenafil (Viagra): can occasionally produce a blue-green tint.
If you recently started a new medication or had a medical procedure involving sedation, check the side effects list. Drug-related color changes are predictable and not dangerous. They stop once the medication leaves your system.
Urinary Tract Infections
Certain bacteria, particularly Pseudomonas species, produce green pigments as a byproduct of their metabolism. A urinary tract infection caused by these bacteria can give urine a greenish color. The key difference from food or medication causes is that a bacterial infection comes with other symptoms: burning during urination, frequent urges to go, cloudy or foul-smelling urine, pelvic discomfort, or fever.
Pseudomonas infections are more common in people who’ve had recent catheterization, hospital stays, or compromised immune systems. If your green urine is paired with any pain, fever, or general feeling of being unwell, an infection is worth investigating with a simple urine test.
Liver and Bile-Related Causes
Your liver produces bile to help digest fats, and one of the pigments in bile, called biliverdin, is green. Normally biliverdin gets converted and processed without affecting your urine color. But when the liver is struggling or bile ducts are blocked, biliverdin can spill into the bloodstream and eventually into your urine, turning it green.
This is rare and associated with serious conditions like liver failure or biliary obstruction. A condition called hyperbiliverdinemia causes green discoloration of urine, skin, and even the whites of the eyes due to elevated biliverdin levels in the blood. If your urine is green and you also notice yellowing of your skin or eyes, dark stools, abdominal pain on the right side, or persistent nausea, those are signs of a liver or gallbladder problem that needs prompt evaluation.
Rare Genetic Causes
In infants, a condition called Blue Diaper Syndrome can cause blue-green urine stains in diapers. First described in 1964, it’s an extremely rare genetic disorder where the body can’t properly process the amino acid tryptophan. Bacteria in the gut convert the unabsorbed tryptophan into indigo-related compounds that are excreted in urine, producing the characteristic blue-green color. This is typically identified in newborns and confirmed through specialized urine testing. If you’re a parent noticing unusual diaper colors, it’s worth mentioning to your pediatrician, though the condition is exceedingly uncommon.
How to Figure Out Your Cause
Start with the simplest explanations. Think back over the last 24 to 48 hours: did you eat anything with bright food coloring, take a new supplement, start a medication, or have a medical procedure? If so, stop the suspected cause and see if your urine returns to normal. For food dyes and most supplements, this happens within a day.
If you can’t identify an obvious dietary or medication cause, pay attention to other symptoms. Green urine on its own, with no pain, no fever, and no other changes, is rarely a sign of anything serious. Green urine paired with burning, abdominal pain, yellowing skin, or fever points toward infection or a liver issue and warrants a urine test or blood work to sort out what’s happening.
The color itself isn’t the problem. It’s a signal. In the vast majority of cases, that signal is simply telling you that a pigment passed through your body exactly the way it was supposed to.