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Home » Green Urine 101: 5 Common Causes & When to Worry.

Green Urine 101: 5 Common Causes & When to Worry.

Common causes of green urine include methylene blue dye, medications such as antihistamines, Pseudomonas UTI, chronic obstructive jaundice, and others.

Here is a breakdown of all possible causes and common questions about green urine.

What are the causes of green urine?

1. Methylene blue dye.

Methylene blue dye is a water-soluble substance that is easily excreted in the urine.

This substance is commonly used in:

  • During radiological scans (computed tomography).
  • During surgery: surgeons use the dye to test the integrity of an anastomosis (connecting to adjacent channels as intestinal anastomosis).
  • Used as an injection drug to treat a disease called Methemoglobinemia.

Methylene blue is blue, but it causes green urine as the blue pigment combines with the yellow urine pigments resulting in green color. The color of urine may range from blue, bluish-green, lime (yellowish-green), or light (bright) green color.

2. Medications.

Medications are one of the most common causes of occasional green color. Many drugs contain green or blue chemicals that appear in the urine leading to a green or lime urine color.

Always review any recent medications before the onset of green urine. Other urinary symptoms, such as bladder pain (lower abdominal pain), dysuria (burning urination), or abnormal urethral discharge, are NOT caused by medications that cause green urine


Also, green urine due to medication is often a temporary condition. You should expect urine to return to its normal amber-yellow color within a few hours or 1-2 days.

Prolonged green urine without taking any medications or the presence of other urinary symptoms often excludes the

  • Indomethacin (Indocin® and Tivorbex®) is a nonsteroidal anti-inflammatory drug used for pain and fever.
  • Metoclopramide is a medicine that treats nausea, vomiting, and slow stomach emptying (gastroparesis).
  • Amitriptyline: is a medicine that treats mood disorders such as depression. It may also be used.
  • Propofol: a drug that is commonly for anesthesia (during surgeries).
  • Promethazine (Phenergan®) is an antihistaminic drug (used for allergic conditions such as skin rashes, cough, etc.). It also has anti-nausea effects.
  • Cimetidine (Tagamet®) is another anti-histamine used for acid reflux (GERD), peptic ulcer disease, and gastritis.
  • Metronidazole (Flagyl®): a very common antibiotic used in gastrointestinal infections and others. Green urine is rare with metronidazole but can occur (especially in children). Green urine with metronidazole is a being and self-limiting.
  • Other medications:
    • Anthraquinone.
    • Clioquinol.
    • Flupirtine.
    • Guaiacol.
    • Listerine.
    • Magnesium Salicylates.
    • Phenyl butazole

3. Artificial dyes.

Water-soluble green and blue dyes are often present in food colorings and some herbal and traditional medicines.

Note that the dye color can be either green or blue. Blue dyes give green color when it mixes

Common dyes that may cause green urine to include (reference):

  • Methylene blue
  • Boric acid.
  • Carbolic acid.
  • Evans blue.
  • Flavine derivatives.
  • Food colorings
  • Indigo blue.
  • Indigo carmine.

Common examples:

  • Eating too many mint-flavored Clorets
  • Green beer.
  • Excessive use of mouthwash or deodorants.
  • Traditional medicine products and herbal supplements.
  • Herbicide poisoning.

4. UTI caused by pseudomonas.

The most common cause (about 90%) of urinary tract infections is E. coli bacteria.

Pseudomonas aeroginusa is a bacteria that may cause urinary tract infections in rare cases.

Pseudomonas-related UTIs may present with green urine. The green color of urine is due to the production of a pigment called (pyocyanin) by the bacterium (reference).

Symptoms of UTI:

  • Dysuria (pain during urination).
  • Urinary frequency (frequent urge to pee but only small amounts of urine comes out).
  • Smelly urine.
  • Cloudy, smokey or turbid urine.
  • Frequent waking up to pee at night (nocturia).
  • Sudden urge to pee (urgency).
  • Bladder pain (lower abdominal and lower back pain).
  • Blood in the urine (hematuria).

5. Chronic obstructive jaundice.

Bile is formed mainly from a yellowish-brown substance called bilirubin. it is formed inside the liver and excreted to the small intestine via the bile ducts.

When the bile ducts become obstructed, bilirubin levels increase in the blood and pass through the kidney leading to brown or tea-colored urine.

However, in chronic cases, bilirubin may break down into another substance called (biliverdin) which is greenish in color. The passage of biliverdin in urine leads to green or greenish-brown urine.

Chronic obstructive jaundice is caused by:

  • Gallstones obstruct the common bile duct.
  • Pancreatic head cancer.
  • Common bile duct strictures.
  • And others.

Symptoms of chronic obstructive jaundice:

  • Attacks of biliary colic (right upper abdominal pain that comes and goes in attacks).
  • Yellowish eye whites.
  • Yellowish skin, mouth, and tongue.
  • Brown, green, or greenish-brown urine.
  • Symptoms of the causes such as nausea and vomiting with gallstones, weight loss and diarrhea with pancreatic cancer, etc.
  • Pale or clay-colored stools.

6. Other causes of green urine.

Many rare diseases and substances can lead to green urine (reference):

  • Blue diaper syndrome.
  • Hartnup disease.
  • Indicanemia.
  • Meconium aspiration syndrome.
  • Typhus.
  • Vesico-enteral fistula.
  • Arbutin.
  • Azuresin.
  • Blutene.
  • Bromoform.
  • Thymol.
  • Tetralin.
  • Phenol.
  • Tolonium.

Questions to ask yourself if you have green urine.

To figure out the cause of green urine, you can ask yourself the questions in the table below, which will help you figure out the possible cause of green urine.

SymptomsPossible cause
Recent intake of drugs such as antihistamines, amitriptyline, etc.Drug-induced green urine.
Green urine after surgery.Propofol is used in anesthesia, or methylene blue is used during surgery.
Recent radiological scans with an injection of dye.Methylene blue.
Burning urination, frequency, lower abdominal pain, smokey or smelly urine.Psudomona aeroginosa UTI.
Jaundice (yellow skin and eye whites), upper right abdominal pain, or known to have pancreatic cancer.Biliverdin in urine due to obstructive jaundice.
Recent intake of green beer, Clorets, or herbal supplements.Food colorings and artificial dyes.
Overuse of mouthwash or mouth deodorant.artificial dyes

1. When to worry/see a doctor for green urine.

See a doctor for green urine if there are:

  • Prolonged greenish discoloration of urine for days without an obvious cause.
  • Severe burning urination or frequent urge to pee.
  • Cloudy, smokey, or turbid urine.
  • Unexplained abdominal pain.
  • Jaundice or clay (pale stools).
  • Fever.
  • Nausea or vomiting.
  • Severe abdominal pain.
  • Accidental intake of abnormal chemicals (poisoning) such as herbicides.

. FAQs:

1. What causes the green urine in a pregnant woman?

Green urine in pregnant women can be due to Pseudomonas aeroginosa UTI, certain medications, greenish or blue food and beverage colorings, and overuse of mouthwash or deodorants. Always consult your doctor if you have persistent green urine.

2. What causes green poop and urine at the same time?

Green poop and urine can be caused by ingesting artificial dyes (as in mouth washers), some medications and supplements, or food colorings (such as green beer, Clorets, etc.). Always consult your doctor if you have other associated symptoms, such as severe diarrhea, abdominal pain, or burning urination.

3. Does green urine mean I have an STD?

In most cases, green urine color doesn’t mean you have STD. Some medications, artificial dyes, and food colorings cause green urine. However, Gonococcal urethritis (an STD) may cause green urethral discharge but not green urine.

4. What causes green urine after surgery?

Green urine after surgery is often due to an anesthetic medication called propofol or a water-soluble dye called methylene blue (used by a surgeon to determine the integrity of the anastomosis).

5. Can nitrofurantoin cause green urine?

Nitrofurantoin is a drug commonly used to treat urinary tract infections. However, Green urine is not a reported side-effect of nitrofurantoin. Check for other causes of green urine Pseudomonas aeroginosa UTI, artificial food colorings, and other medications such as metoclopramide, antihistamines, etc.

6. Can iron supplements cause green urine?

Iron supplements are known to cause green or dark poop. However, green urine is not a reported side effect of iron supplements. Check for other causes of green urine, such as medications, herbal supplements, Clorets, green beer, etc.

7. Does the Keto diet cause green urine?

The Keto diet itself is not known to cause green urine. However, people on keto often consume a variety of multivitamins and supplements, and some artificial coloring in multivitamins and herbals may lead to green urine.

8. What is the link between vitamin B supplements (containing riboflavin) and green urine?

Vitamin B complex supplements often contain riboflavin (vitamin B2). It is a yellowish-green fluorescent pigment that may lead to bright (fluorescent or neon) yellow or lime urine when you take vitamin B supplements.