Red pee has a wide range of causes, from completely harmless foods to conditions that need medical attention. The color can come from actual blood in your urine, but it can also come from pigments in food, medications, or intense exercise. Even a tiny amount of blood is enough to turn urine visibly pink or red, so the appearance alone doesn’t tell you how serious the situation is.
Foods That Turn Urine Red
Beets are the most common dietary culprit. They contain a red pigment called betanin that passes through some people’s digestive systems without being fully broken down, coloring the urine pink or red. This phenomenon, sometimes called “beeturia,” is harmless and typically clears within a day or two after eating beets. Rhubarb can produce a similar effect.
Not everyone who eats beets will notice a color change. The trait has been linked to differences in how individuals absorb and metabolize the pigment, and some research suggests it may be more common in people with lower iron levels. If you ate beets or a beet-heavy juice in the last 24 to 48 hours, that’s very likely your answer.
Medications That Change Urine Color
Several common medications can make urine look red, orange, or reddish-brown:
- Phenazopyridine: A bladder pain reliever often prescribed alongside antibiotics for urinary tract infections. It reliably turns urine bright orange to reddish-orange.
- Rifampin: A tuberculosis medication that produces reddish-orange urine.
- Senna-based laxatives: Over-the-counter constipation remedies containing senna can shift urine color toward red or orange.
- Sulfasalazine: Used for inflammatory bowel conditions, this can also produce orange-tinted urine.
If you recently started any new medication and noticed the color change, check the drug’s side effects. Medication-related color changes are cosmetic and not harmful to your kidneys or bladder.
Blood in the Urine (Hematuria)
When the red color actually comes from blood, the medical term is hematuria. Blood in your urine can make it look pink, red, or cola-brown. It takes a surprisingly small amount of blood to visibly change the color, so even a dramatic-looking sample may involve minimal bleeding.
The most common causes of blood in urine include:
- Urinary tract infections (UTIs): Bacteria enter the urethra and multiply in the bladder. You’ll usually also have burning during urination, a frequent or urgent need to pee, and possibly pelvic pressure or cloudy urine.
- Kidney stones or bladder stones: Hard mineral deposits that irritate or scrape the urinary tract lining. Stones typically cause sharp pain in the side or lower back that comes in waves, along with nausea.
- Enlarged prostate: In men over 50, a growing prostate can press on the urinary tract and cause bleeding, along with difficulty starting urination or a weak stream.
- Vigorous exercise: Long-distance running, cycling, and contact sports can all cause temporary blood in the urine (more on this below).
- Recent sexual activity or minor trauma: Both can cause short-lived, harmless bleeding.
More serious but less common causes include bladder or kidney cancer, blood-clotting disorders like hemophilia, sickle cell disease, and kidney diseases that damage the filtering units of the kidneys. A large European review found that among people who saw a doctor for visible blood in their urine, about 17% were ultimately diagnosed with bladder cancer. That number is higher than the general population because it reflects people who sought medical evaluation, but it underscores why persistent or unexplained blood in the urine deserves a workup.
Exercise-Related Red Urine
Intense physical activity is a surprisingly common trigger. During hard exercise, blood flow shifts away from the kidneys and toward working muscles, which temporarily makes the kidney’s filtering membranes more permeable. Small amounts of blood can leak through. In contact sports, the bladder itself can bounce against the pelvic bone repeatedly, causing direct irritation.
There’s also a second mechanism: muscle breakdown. When muscles are pushed to their limits, damaged muscle cells release a protein called myoglobin into the bloodstream. Myoglobin is filtered by the kidneys and can turn urine dark red or brown. This is different from actual blood cells in the urine, but it looks similar. Studies estimate that up to 95% of athletes show microscopic blood in their urine after intense exercise, and muscle-related pigments contribute to visible color changes in roughly 30% of cases.
Exercise-induced red urine is almost always temporary, clearing within 24 to 72 hours. If it persists beyond three days or happens repeatedly without an obvious exercise trigger, it warrants a closer look.
Rarer Causes Worth Knowing
Porphyria is a group of inherited disorders where the body can’t properly produce heme, a component of hemoglobin. When this process is disrupted, intermediate compounds called porphyrins accumulate in the liver or bone marrow and are eventually excreted in urine, sometimes giving it a reddish or port-wine color. Porphyria is uncommon, but the urine color change can be one of its earliest noticeable signs, often alongside abdominal pain, skin sensitivity to sunlight, or nerve symptoms like tingling.
Kidney disease that affects the glomeruli (the tiny filtering clusters in the kidneys) can also cause persistent blood in the urine. This type of bleeding is often microscopic, only visible under a lab microscope, but it can occasionally produce visible discoloration. A recent strep throat or viral infection sometimes triggers this kind of kidney inflammation, particularly in children.
How Doctors Evaluate Red Urine
The first step is a urinalysis, which can distinguish between actual blood cells, free hemoglobin from broken-down red blood cells, and myoglobin from damaged muscle. If you spin a urine sample in a centrifuge and the red color settles to the bottom with clear liquid on top, it’s blood cells. If the liquid stays colored, it’s hemoglobin or myoglobin, and a blood test can tell those two apart.
If blood cells are confirmed, doctors assess your risk based on factors like age, smoking history, and how much blood is present. For people at lower risk, a repeat urine test in six months may be all that’s needed. Intermediate-risk patients typically get an ultrasound of the kidneys along with a cystoscopy, a procedure where a thin camera is passed into the bladder to look at the lining directly. High-risk patients, particularly smokers over 50 with visible blood, get more detailed imaging of the entire urinary tract.
Clues That Help You Sort It Out
Before you panic, think through a few quick questions. Did you eat beets, rhubarb, or anything with heavy red food coloring in the last day or two? Are you taking any new medication? Did you just finish a hard workout or long run? If the answer to any of these is yes, that’s the most likely explanation. Wait a day, stay hydrated, and see if the color returns to normal.
Red flags that point toward something more serious include blood clots in the urine, pain in your side or lower back, burning or difficulty urinating, fever, or red urine that persists for more than a couple of days without an obvious dietary or medication explanation. Painless red urine that comes and goes over weeks is also worth investigating, since bladder and kidney cancers often cause intermittent, painless bleeding rather than constant symptoms. People who take blood thinners or aspirin regularly are more prone to hematuria as well, since these medications make it easier for even minor irritation to produce visible bleeding.