Changes in urine – When to see the doctor

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Most people take bladder and bowel control for granted — until something goes wrong. An estimated 32 million Americans have incontinence, the unintended loss of urine or feces that is significant enough to make it difficult for them to maintain good hygiene and carry on ordinary social and work lives. The good news is that treatments are becoming more effective and less invasive. This Special Health Report, Better Bladder and Bowel Control, describes the causes of urinary and bowel incontinence, and treatments tailored to the specific cause.

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Urine is simply excess water and waste products that your kidneys filter from your blood. Its color usually ranges from pale yellow to deep amber, depending on its concentration — the proportion of waste products to water. That, in turn, depends partly on how much fluid you consume.

For the most part, we pay little attention to urine, unless it looks or smells unusual. A surprising number of things can affect the color and odor of your urine. The most common ones are harmless and temporary, including foods, vitamins, and certain medications. But sometimes changes in urine signal a medical problem, which may range from relatively benign (a urinary tract infection) to serious (kidney or bladder cancer). Here are some suggestions on when you can relax and when you should consult your clinician.

Vegetables, fruits, and vitamins

Beets, blackberries, and rhubarb can temporarily turn urine pink or red, which can be alarming, because it may be mistaken for blood. The pigment that gives beets their deep magenta color is stable only at certain levels of stomach acidity and is usually too faint to show up in most people's urine. The phenomenon — dubbed "beeturia" — occurs in only about 10% to 14% of the population. Even if you're in that select group, eating beets won't always have a visible effect, because the acidity of your stomach (and therefore your urine) depends on when you ate and what else you ate. Rhubarb can also turn urine dark brown or tea-colored, as can fava beans and aloe. Carrots, carrot juice, and vitamin C can color urine orange, and B vitamins can turn it a fluorescent yellow-green.

Asparagus sometimes gives urine a greenish tinge and a distinctive smell. Why this occurs is a matter for speculation. Some blame it on the sulfur-containing fertilizers used on asparagus plants (there is no record of the vegetable changing urine odor before such fertilizers were introduced). Others suggest that only people who carry a particular gene break down the sulfur-containing proteins in asparagus that release the odor. Still another view is that the smell of everyone's urine undergoes a change, but only some of us notice it. The current consensus seems to be that some of us produce smelly urine after eating asparagus, and some of us do not, while some can detect the odor and some cannot.

Medications and medical problems

Various prescription and over-the-counter medications can change the look of your urine. So can certain medical conditions, most commonly urinary tract infections (UTIs), which affect about half of all women at least once during their lives. The mucus and white blood cells associated with UTIs can turn urine cloudy and cause an unpleasant odor. Symptoms also include a frequent and urgent need to urinate, burning pain with urination, and abdominal pain. Contact your clinician if you experience these symptoms, which usually disappear quickly after you start oral antibiotics.

Medications associated with changes in urine color

Color of urine



senna (Ex-Lax), chlorpromazine (Thorazine), thioridazine (Mellaril)


rifampin (Rifadin), warfarin (Coumadin), phenazopyridine (Pyridium)

blue or green

amitriptyline (generic), indomethacin (Indocin), cimetidine (Tagamet), promethazine (Phenergan)

dark brown or tea-colored

chloroquine (Aralen), primaquine (generic), metronidazole (Flagyl), nitrofurantoin (Furadantin)

UTIs can also cause blood in the urine (hematuria). If the amount is very small, the urine appears normal, and the blood is visible only under a microscope. Larger amounts can cause urine to appear pinkish, red, or cola-colored.

Another possible cause of hematuria is kidney stones — hard, crystalline masses ranging in size from a grain of sand to a pearl that form within the urinary tract or kidney. A stone may cause hematuria if it irritates the ureter (the tube that carries urine from the kidney to the bladder). Kidney stones can also cause extreme pain in your back or side, and fever, chills, and vomiting, for which you should seek immediate medical attention. But most stones will pass out of the body without medical intervention.

Hematuria can also result from an injury to the upper or lower urinary tract (for example, in a car accident or bad fall). Strenuous exercise (especially running) can sometimes cause hematuria because the repeated jarring damages the bladder. Less common sources of hematuria are bladder cancer and kidney cancer or other kidney disease — so be sure to check with your doctor if your urine appears reddish for no apparent reason.

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Healthy Travel
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In this guide, Healthy Travel, you’ll find the information you’ll need to make sure your vacation is a healthful one, from the plane ride there to your final meal of the trip.

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Can I fly again after having a DVT?

Q. Last year I had a deep-vein thrombosis with a small pulmonary embolism, apparently precipitated by flying across the country without getting up and walking around. I did just fine with anticoagulation and am now off all medications. Is it safe for me to fly again? If so, what precautions would you recommend?

A. Yes, you can fly again, if you take some precautions. Before I describe them, though, I would like to raise an equally important issue for your health and well-being.

The fact that you developed a deep-vein thrombosis (DVT) and a pulmonary embolism (PE) indicates that your blood has a tendency to clot under certain stressful conditions, such as sitting on an airplane for several hours. Having one DVT or PE means you are at high risk for another, even if you avoid air travel. Without an anticoagulant to help protect against blood clots, your chance of having a repeat DVT or PE is about 30% to 50% over the next 10 years. Many doctors, including me, would advise you to take an anticoagulant such as warfarin indefinitely.

Prolonged sitting and dehydration create an environment inside veins that promotes the formation of blood clots. Both are common among airline passengers. Being confined to bed, having a leg in a cast, or other types of immobility also set the stage for a DVT or PE.

Here are four things you, or anyone embarking on a long-haul flight, can do to minimize the chances of developing a DVT or PE.

1. Stay hydrated. Bring extra bottles of water on board and drink enough water to make you get up and use the rest room several times. This will also help with the third tip.

2. Avoid alcohol. Alcohol can dry you out. It can also make you so drowsy that you don't move much (see number 3).

3. Move your muscles. Stand up and stretch your arms and legs at least once an hour. Walk up and down the aisle, or just pace in place. While standing or sitting, do simple exercises such as straightening your knee and stretching your leg, and pointing your toes up, then down. Give yourself more room to move by storing as little as possible under the seat in front of you.

4. Consider compression stockings. Elastic support stockings keep blood flowing by gently squeezing the legs and moving blood back to the heart. This prevents the buildup of fluid around the ankles that ordinarily occurs during long-haul air travel.

— Samuel Z. Goldhaber, M.D.
Professor of Medicine
Harvard Medical School

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