Urine should be pale yellow in color, clear, and odorless.
Changes in the color of your urine — like green, orange, brown, or red — can be a clue to underlying health issues.
The most common cause of green urine is medication, but foods — and food dyes — can also cause it. In rare cases it can be a sign of a bacterial urinary infection or a liver problem.
You’ve probably noticed that the color (and smell) of your urine changes depending on your level of hydration and the time since you last urinated. Certain foods can also affect the appearance of your urine. And if you’ve ever had a urinary tract infection (UTI), you’ve likely noticed a change in the color, smell, and appearance of your urine.
Green pee isn’t a common symptom, but it may cause alarm. Here are 10 causes of green urine. Spoiler alert: Only two of them are really cause for concern (and they’re very rare).
Medications can turn your pee different colors. There are seven medications that can color pee green. The color change is due to a chemical reaction. A blue pigment in the medication mixes with the natural yellow color of urine and makes it look green (or bluish-green).
In many cases, the cause of the color change is something called a “phenol group” in the chemical structure of the drug. When your body breaks it down, it produces blue pigments in your urine. After these mix with the yellow pigments (urochrome) in your urine, the end result is green pee.
Promethazine (Phenergan): an antihistamine that treats allergies and nausea
Metoclopramide (Reglan): an anti-nausea medication
Amitriptyline (Amitril): an antidepressant that treats fibromyalgia and depression
Indomethacin (Indocin): a nonsteroidal anti-inflammatory drug (NSAID)
Propofol (Diprivan): an anesthetic used in surgery
Methylene blue: a water-based dye used in scans, surgery, and in treatment for methemoglobinemia (a rare blood disorder)
Medications aren’t the only thing that can turn your urine green. Other causes of green pee include:
Food dye: artificial green or blue dyes
UTIs: when the cause is the bacteria Pseudomonas aeruginosa
Liver problems: sometimes cause a buildup of bilirubin in the body
When the cause of green pee is medication, there’s usually nothing to worry about. The color should fade within a few hours, or when you stop taking the medication.
There are only two causes of green pee that are serious, and both of them are very rare.
Although very uncommon, a UTI with the bacteria Pseudomonas aeruginosa can cause a bluish-green tinge. This happens because the bacteria produce pyocyanin, a blue pigment.
The other serious cause of green pee is jaundice. This condition can happen if you have serious problems with your liver, pancreas, or gallbladder. Jaundice is a buildup of bile (bilirubin) in the blood that causes a yellowing — and sometimes a greenish discoloration — of the skin, eyes, and urine.
Some people report that asparagus adds a greenish tinge to their urine, but there isn’t hard science to back this up. More commonly, people notice a typical asparagus smell in their urine. But that’s a topic for another day.
Some people also list vitamin B complex as a cause for green urine. Riboflavin (vitamin B2) does have a yellow-green fluorescent pigment, but this causes urine to turn a brighter yellow — not green.
Healthy urine should be a pale, clear yellow color. When you’re dehydrated, your urine may turn darker and have a stronger smell — that’s your body doing its job to avoid wasting fluid.
But if you notice that your urine is consistently dark yellow, orange, brown, red, or tinged with blood, then that may be a sign that there’s something else going on.
In addition to the color, other things to pay attention to are:
How often you need to urinate
How much urine you produce
Your urine’s appearance (for example, if it’s cloudy or foamy)
Changes in smell (strong, unpleasant, sweet)
If you see a noticeable or consistent change in any of these characteristics, it's best to see a healthcare provider. Oftentimes, a simple urine test can figure out if something is wrong.
Preschool teachers and parents alike enjoy adding green food coloring to the toilet water on St. Patrick’s Day. This surprises kids with “leprechaun pee.”
But are there other causes of green pee on this holiday?
Every year on St. Patrick’s Day, restaurants, bars, and pubs around the country offer up green beers, burgers, shamrock shakes, and other foods and drinks colored with green food dyes.
So can consuming a day’s worth of green alcohol cause green pee? The answer is yes, possibly. Green pee may continue for 12 hours or so after you finish eating or drinking things that have artificial green food dye. But if your urine stays green for longer than 24 hours, there may be something else going on.
Most cases of green urine are nothing to worry about — especially when the symptom is brief or you recently started a new medication. But if the green foods of St. Patrick's Day have passed and you continue to notice changes in your urine, it’s best to seek medical evaluation. Your provider can run some simple tests to see if this is a sign of something else going on.
Mahabadi N., et al. (2022). Riboflavin deficiency. StatPearls.
Pelchat, M. L., et al. (2011). Excretion and perception of a characteristic odor in urine after asparagus ingestion: A psychophysical and genetic study. Chemical Senses.
Prakash S., et al. (2017). Green urine: A cause for concern? Journal of Anaesthesiology Clinical Pharmacology.
Simerville J. A., et al. (2005). Urinalysis: A comprehensive review. American Family Physician.
Urology Care Foundation. (2018). The meaning behind the color of urine.
Uniprot. Disease - Hyperbiliverdinemia.