What the colour of your urine means
The yellow colouration in urine is a result of urobilin, a chemical by-product of bilirubin degradation (which occurs when your kidneys process waste).
A pale to golden yellow hue is considered normal and healthy and reflects a good balance of hydration. A fluorescent yellow hue is normally caused by B vitamins, especially B12. A darker, more concentrated yellow hue can be a result of pigments found in foods and multivitamins.
A very dark yellow colour can be an indication that you’re dehydrated and hydration levels need to be increased through fluid intake.
Red urine can vary in intensity from a light clear pink (think pink lemonade) to bright red (think tomato soup) to a deep dark red (reminiscent of Merlot).
Certain pigment-containing foods can effect a change in urine colour and cause a red or light pink hue which usually clears back to a normal yellow colour within the next day or two. These foods include:
Red urine can also be an indication of blood in the urine which may be due to underlying health issues. Blood in the urine (haematuria) is considered one of the most common causes of red urine. This could be a result of:
- Contamination due to menstruation
- Malignancy (a tumour in bladder or kidneys)
- Renal disease
- Stone disease (kidney stones)
- Porphyria (a group of rare inherited disorders wherein heme (part of haemoglobin) is not manufactured correctly by the body)
Other medical causes of red urination include haemolytic disorders such as March haematuria and myocyte destruction caused by a crush injury. Both lead and mercury poisoning also cause red discolouration.
Various medications are also known to cause red discolouration in the urine such as:
- Chlorpromazine (an antipsychotic medication)
- Laxatives containing phenolphthalein
- Phenazopyridine (sold under the brand name Pyridium and used to treat urinary tract infections)
- Rifampin (an antibiotic used to treat Tuberculosis)
- Senna (and laxatives containing this)
- Thioridazine (an antipsychotic medication)
If your urine is red and you have not eaten any of the foods or taken any of the medication mentioned above, you should see a medical professional, especially if you notice blood clots and you are not menstruating.
Many of the factors that turn your urine red can also be responsible for an orange discolouration. The overconsumption beta-carotene found in sweet potatoes and carrots can turn both urine and skin orange.
From a medical perspective, florescent orange urine paired with yellow tinted eyes can be an indication of issues within the liver.
Additionally, orange urine can also be caused by consuming certain medications such as:
- Riboflavin (Vitamin B2)
- Warfarin (if haematuria is absent)
- Sulfasalazine (prescribed to treat rheumatoid arthritis, ulcerative colitis, and Crohn's disease)
- Phenazopyridine (used to treat urinary tract infections)
- Rifampin (an antibiotic commonly prescribed to treat tuberculosis)
Brown urine can be a result of the same numerous causes of red urine. Brown urine can be attributed to anything from eating certain foods to the administration of new medication or be a sign of a more serious health issue.
The over-consumption of certain pigment-containing food has also been known to cause a cola-coloured hue such as:
- Fava beans
- Certain food colourings
The use of certain medications can also lead to brown urine. These include the following:
- Antibiotics nitrofurantoin (Macrobid), metronidazole (Flagyl)
- Antibacterial medications like furazolidone (Furoxone)
- Primaquine (an antimalarial medication)
- Chloroquine (an antimalarial drug)
- Certain laxatives (containing senna and cascara)
- Levodopa (prescribed in the treatment of Parkinson’s disease)
Should your urine appear brown and you have not consumed the above-mentioned food and medication, you should see your doctor immediately to investigate medical causes of this condition.
Often, sediment from old blood clots looks brown when released in a certain concentration of urine. Similarly, haemoglobinuria (the excretion of haemoglobin, a red protein responsible for transporting oxygen in the blood, that is then seen in urine) and myoglobinuria (the excretion of a protein, myoglobin, which is usually found in the muscle cells, in the urine) caused by a condition known as rhabdomyolysis which develops as a result of muscle injury, often give urine a brownish hue.
More serious causes for brown coloured urine include medical conditions such as:
- Severe dehydration
- Urinary tract infection (UTI)
- Bleeding within the urinary tract
- Haemolytic anaemia (a condition that develops when red blood cells are destroyed)
- Kidney disorders and disease
- Melanoma, a type of skin cancer wherein melanin (the pigment responsible for giving skin its colour) may be excreted through the urine.
- Acute tubular necrosis (the death of the epithelial cells within the renal tubes of the kidneys)
- Liver disorders (hepatitis, cirrhosis) and liver failure (usually accompanied by jaundice)
- Porphyria (these are a rare class of inherited conditions that involve sensitivity to light and cause brownish coloured urine due to the different way in which red blood cells are produced and broken down)
Just as the causes of red urine affect orange and brown urine colouration, black urine can be a result of the same causes depending on the concentration and intensity level of the urine colour change.
Foods that cause black urine when consumed in excess include:
- Fava beans
- Food colourings and dyes
- Sorbitol (a commonly used sweetener)
Certain medicinal causes have been known to cause black discolouration such as:
- Feminine hygiene douches
- Ingesting iodine
- Antimalarial drugs chloroquine and primaquine
- Nitrofurantoin (Macrobid) and metronidazole (Flagyl) – common antibiotics
- Furazolidone (Furoxone) – an antibacterial medication
- Laxatives made from Senna leaves and cascara bark
- Methyldopa (Aldomet) – used to treat high blood pressure
- Levodopa (used in the treatment of Parkinson’s disease
- Methocarbamol (skeletal muscle relaxant)
- Phenacetin poisoning (due to prolonged use or overdose with phentacin containing pain killers)
- Phenol poisoning (due to contact with disinfectants)
- Copper poisoning
Medical conditions that can cause a black coloured urine include the following:
- Alkaptonuria which is a genetic disease can cause urine darkening when the urine is exposed to air due to the build-up of by-products produced as a result of this genetic condition.
- Melanoma – this form of skin cancer leads to the secretion of melanin and melanogen which can turn urine black if present therein.
- Haemoglobin production in porphyria can cause brownish urine that creates the appearance of black urine when exposed to sunlight. This is especially encountered in patients with Porphyria Cutanea Tarda.
- Blackwater fever as a result of complications in malaria treatment wherein the red blood cells are broken down, releasing haemoglobin which appears dark red or black when passed through urine.
- Liver disease (hepatitis, cirrhosis and liver failure)
- Cancer of the bladder, kidneys, prostate or pancreas
- Wilms tumour – kidney cancer affecting children
You should contact your medical care provider immediately should you be experiencing black urine.
Purple urine is extremely rare. As with other urine discolourations, porphyria can be a cause of purple urine when it is exposed to sunlight.
Another cause for purple discolouration is purple urine bag syndrome (PUBS), whereby catheter urine collection bags and tubing are changed to a purple hue due to the presence of colonising bacteria as a result of a urinary tract infection (UTI).
Blue urine is mostly caused by iatrogenic conditions (i.e. conditions caused by medical treatments or examinations). For example, the ingestion of a large amount of methylene blue, which is found in home remedies, supplements or medications. Another example would be an intravenous injection of methylene blue or indigo as part of a diagnostic procedure or in the treatment of cyanide poisoning and an inherited blood disorder known as methemoglobinemia.
Another cause for blue urination is familial hypercalcemia, a rare genetic disorder, wherein the affected person has an excessive amount of calcium in their bones.
Blue urine could be a sign of a serious issue and should be consulted with a doctor should it be experienced.
Green urine can also be a result of the same conditions that cause blue urine when combined with the yellow colour produced by urochromes in urine.
Certain pigment-containing foods can affect your urine and turn it green. These foods include:
- Black liquorice
- Artificial food colouring
There are medications and supplements that have been linked to producing green-hued urine, such as:
- Amitriptyline used to treat anxiety and depression.
- Cimetidine used to prevent certain types of ulcers and treat gastroesophageal reflux disease (GERD).
- Indomethacin, a nonsteroidal anti-inflammatory drug.
- Medication containing phenol
- Metoclopramide treats symptoms such as heartburn, nausea and loss of appetite.
- Promethazine prevents motion sickness and treats nausea or pain after surgery. It is also used to treat allergy symptoms such as runny nose, hives, itching, itchy or watery eyes and itchy skin rashes.
- Rinaspin (an antibiotic)
Certain medical conditions have been known to cause a green discolouration in urine. For example, a pseudomonas related urinary tract infection caused by Pseudomonas aeruginosa bacteria often results in green urine. Urine can also be turned green by diarrhoea, pus from a urinary tract infection or fistulas found in the urinary tract, which help to bile move into the urine stream, release green pigment that stains the urine.
Also known as albuminuria (or albumin in the urine), cloudy or milky white urine mostly occurs due to sediment. A snowy or white colouration can also be the result of mineral crystal presence such as those from calcium or phosphate precipitation.
Certain medical conditions have been known to cause white or 'cloudy' urine. These include:
- Urinary tract infections (UTIs)
- Mucus in the urine
- Mycobacterial infection
- Pyuria (the presence of pus in urine, generally due to a bacterial infection)
- Kidney stones
- Lymphatic drainage into the urinary tract
- Chyluria (the presence of chyle, a milky lymphatic fluid containing fat droplets in the urine, this can be a result of parasitic or non-parasitic infection).
If your urine appears white, you should seek medical advice immediately.