Urine can occasionally turn a bright yellow color. Urine can adopt a wide range of colors, and each has a different meaning for health status.
Often, dehydration causes bright yellow urine. This article discusses the triggers of color changes in the urine.
The article also takes a look at different factors that affect urine color. Certain foods, vitamins, and medications can have an impact on the way urine looks and smells,
An excess of B-vitamins can cause bright yellow urine.
Bright yellow urine is a sign of excess B-vitamins in the body, including B-2 and B-12, although this condition is harmless.
Taking B-vitamin supplements can lead to urine of this color.
The yellow color darkens as the concentration of the urine increases. Concentration refers the proportion of waste products to water.
The urine darkens as the concetration increases, because the body takes in less fluid. This also happens if fluid is lost by other means, such as sweating.
People use the yellow in urine to indicate fluid balance in the body. Urine color is also a reliable way to monitor hydration levels during exercise.
What gives urine its healthy yellow color?
The yellow color in balanced urine comes from urochrome, a waste product that comes from the breakdown of hemoglobin. Hemoglobin is the protein in red blood cells that enables oxygen to travel around the body.
Red blood cells are renewed in their millions every day, so the body needs to break down old cells. The urochrome from this process ends up in the urine as a yellow color.
Darker shades of yellow suggest that an individual may be dehydrated and needs water.
While bright yellow urine does not necessarily indicate dangerous health issues, it is important to keep a close eye on the color of urine.
Urine can turn a range of colors, and some highlight a medical problem.
This section names many of the possible causes, but it is not a complete list. There may be other causes of color changes in the urine. People should take any concerns about unusual urine color to a doctor.
However, a visit to a physician may not always be necessary.
Bright yellow urine
An excess of B-vitamins in the blood can cause urine to become bright yellow.
Loose blood components in the urine can turn it red.
Drugs containing phenol, dyes, and infections can turn the urine green.
Antipsychotic and antibacterial medication can turn urine brown.
Certain drugs and medications can lead to orange urine.
Examples include the antibiotic rifampicin and the pain-relief drug phenazopyridine. Some laxatives and chemotherapy agents can also color the urine orange.
Dietary factors behind orange urine include a high intake of carrots, as a substance called carotene that these vegetables contain can impact urine color. Vitamin C, blackberries, beetroot, and rhubarb can also have this effect.
Red coloring in the urine has a number of causes.
Blood in the urine, known as hematuria, is a possible cause of red urine. See a doctor about red urine, as hematuria can be serious.
Hemoglobinuria, a blood condition, can also cause red urine, as can myoglobinuria, which involves a waste product of the breakdown of muscles.
Harmless causes of redness in the urine include beetroot or blackberries in the diet.
Medicines that turn urine brown include:
- antipsychotic drugs, such as chlorpromazine (Thorazine) and thioridazine (Mellaril)
- antibiotics, such as metronidazole (Flagyl) and nitrofurantoin (Furadantin)
- phenytoin, or Dilantin, an epilepsy drug
- sennoside laxatives, such as Senna-Lax and Senokot)
Deep purple urine
A condition called porphyria causes urine to appear deep purple.
Porphyria is a rare metabolic disorder.
The urine can turn green because of the following:
- drugs and other compounds containing phenol, such as promethazine, used for allergy and nausea, and propofol, a drug used in anesthetics
- other drugs, including the antidepressant amitriptyline, cimetidine, which reduces stomach acid, and the painkiller indomethacin
- dyes, including indigo-blue, indigo carmine, used in kidney tests, carbolic acid, and flavin derivatives
- biliverdin, a bile pigment
- infection with Pseudomonas bacteria
- Methylene blue, a dye that has also been used as a drug, can produce a blue-green color to the urine.
Medical journals often publish case reports, such as this 1999 study of an unusual instance of green urine.
The authors cited ulcerative colitis, a bowel condition, as the cause of the green color. The authors wrote that the gut lining was absorbing green food coloring that it would normally filter out.
Other urine changes
Urine can indicate changes in the body through its smell, clarity, and translucency as well as color.
Cloudy urine can signal a number of possible problems. For women, it could be a result of vaginal discharge.
Other changes that may cause cloudiness include:
- urinary bladder infections and lower urinary tract infections (UTIs)
- kidney disease, including kidney stones
Infection can also cause white or milky-looking urine. Excessive levels of certain minerals, such as calcium, can cause white urine, as well as too much protein in the urine.
Kidney problems and excess protein can also make the urine foamy. Temporary foaminess is usually a result of an unsteady urine flow. If cloudiness in the urine lasts for more than a few days, a doctor should investigate the cause.
The smell of urine can change. Some changes are harmless, while others are a sign of disease:
- Eating a lot of asparagus can make the urine smell like rotting cabbage.
- UTIs can cause the urine to have a foul smell.
- Urine that smells sweet could be a sign of diabetes.
When to see a doctor
Most cases of urine color changes do not need medical attention.
Many of the changes in urine color are temporary or reversible following a change in diet or medication. Most changes are harmless.
Seek medical help whenever dehydration is caused by illness, or if the person is unable to take in fluids. This is especially important if there is no explanation for the dehydration, or it is severe.
Dehydration can be dangerous for anyone, but especially young children or older adults.
A clear indicator for seeking medical help is red-colored urine. If there is any doubt about the cause of a change in the urine, people should see a doctor.
Some conditions that change urine color are rare but serious. A tumor in the urinary tract is one example of a rare cause that needs an urgent diagnosis.
Seeing a doctor is also important if any changes last longer than 2 or 3 days or accompany other symptoms.
Is bright yellow urine a reason to worry?
No, bright yellow urine is not a cause for concern.
The most common reason for having bright yellow urine is not drinking enough water. Other reasons include the food, medications, or vitamins you may have consumed.
First, try to identify the culprit. See if your urine turns a lighter yellow after adjusting your food intake, stopping vitamins, or increasing your water consumption. If this does not help, then speak to your primary care physician.
Do not stop taking any current medications without letting your doctor know. If your bright yellow urine is accompanied by pain with urination, then seek medical attention.Alana Biggers, MD, MPH Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.