Mucus in Urine: Causes, Symptoms, and When to Seek Care

This guide explains what mucus in urine means, its possible causes and related symptoms, and when to seek care. A small amount may be normal, while a large amount can have several causes⁴.

Urine tests can help tell normal mucus from infection, stones, or material mixed into the sample^1,4. Symptoms also help a clinician decide which tests may be useful.

Mucus is a thick, slippery fluid that coats and moistens parts of the body⁴. These parts include the urinary tract, which carries urine from the body⁴.

Mucus helps coat and protect the urinary tract⁶. As it moves through the tract, it may help wash away germs⁶.

Finding mucus in urine does not always mean that something is wrong. A small amount of mucus in urine is normal⁴. A small or moderate amount may also be a normal test result⁴.

A large amount may occur with a urinary tract infection, known as a UTI⁴. Other conditions listed in information about the test include an STI, kidney stones, and irritable bowel syndrome (IBS)⁴.

Urinary mucus can look thin and fluid-like⁶. It may appear clear, white, or off-white⁶.

Mucus may sometimes seem more noticeable because it came from the vagina⁶. Cervical mucus changes in color, thickness, and amount during the menstrual cycle⁶. Pregnancy can also change cervical mucus⁶.

An increase or color change may need medical review⁶. Appearance alone cannot show where the mucus began or what caused it.

Mucus is only one material that can affect how urine looks. Cloudiness may come from bacteria, blood cells, crystals, semen, or vaginal secretions.

Other materials can also enter urine or the sample cup. Possible sources include the following:

Cloudy urine can occur with a UTI, but it does not prove infection. Urine tests can show which cells, germs, crystals, or other matter are present⁵.

Symptoms beside mucus can provide useful clues. They may point toward infection, a stone, or genital discharge.

Cystitis is an infection of the bladder. Common symptoms include burning, frequent urination, urgency, and lower abdominal discomfort.

Other UTI symptoms can include these changes:

Urethritis means swelling or irritation of the tube that carries urine outside. It may cause painful urination, fever, or discharge from the urethra.

A UTI is not the only cause of painful urination. Sexually transmitted infections, skin problems, and bladder irritants can also cause it¹⁰.

Pyelonephritis is an infection of one or both kidneys. It may cause fever, chills, side pain, nausea, and vomiting. Symptoms of a bladder infection may occur at the same time.

Side pain is also called flank pain. It affects the area between the upper abdomen and back.

Kidney stones are hard deposits made from minerals and salts⁶. A stone may cause no symptoms while it remains inside a kidney⁶. Symptoms can begin when the stone enters the urinary tract⁷.

A moving kidney stone may cause the following symptoms:

These symptoms can overlap with those of an infection. A urine test and other tests can help find the cause^5,9.

A sexually transmitted infection, known as an STI, may cause mucus or discharge. Chlamydia and gonorrhea can increase mucus found in urine⁶.

Chlamydia may cause several other symptoms:

Gonorrhea may also cause pelvic pain and painful urination⁶. Discharge may look yellow or green⁶. Vaginal bleeding outside a period may also occur⁶.

Vaginal discharge makes a UTI less likely as the cause of painful urination¹⁰. A clinician may check for cervicitis, which means swelling of the cervix¹⁰.

Possible causes of mucus in urine range from normal secretions to infection. The material may also come from the genital or digestive tract.

The urinary tract makes mucus that helps coat and protect its lining^4,6. A small amount can therefore be normal⁴.

Normal vaginal discharge may also look like urinary mucus⁶. Menstruation, ovulation, pregnancy, and birth control can make this discharge more noticeable⁷.

No treatment may be needed when there are no unexpected or lasting changes⁷. A clinician should assess changes in the amount or color^6,7.

Contamination means that material entered the sample from another source. Bacteria, skin cells, and genital secretions may enter during collection.

Menstrual blood can affect a urine sample. If you have bleeding hemorrhoids, tell your provider before the urine test⁴.

A contaminated sample can make the result harder to understand. A clean midstream sample reduces bacteria, cells, and other material from outside the urinary tract.

A UTI occurs when germs enter the urinary system and cause infection. UTIs may involve the urethra, bladder, ureters, or kidneys.

A large amount of mucus may be a sign of a UTI⁴. Burning, urgency, frequency, and lower abdominal pain commonly occur with bladder infection.

Cloudy or bad-smelling urine may also occur^4,9. Blood can appear in urine during a UTI^6,9.

Kidney involvement may cause fever, chills, side pain, nausea, or vomiting. These symptoms give more information than mucus alone.

For more guidance, read about UTI symptoms, treatment, and when to seek care.

A large amount of mucus may be a sign of a medical condition⁴. Chlamydia and gonorrhea are linked with excess mucus or discharge⁶.

These infections can also cause urethritis. A clinical history can help identify signs of an STI and lower urinary symptoms in males¹⁰. Testing for *Mycoplasma genitalium* is recommended when urethritis persists despite negative initial tests¹⁰.

Not all urethritis comes from sexual contact. Trauma and other noninfectious causes can also inflame the urethra.

Prostatitis is an infection or inflammation involving the prostate gland. Its symptoms can resemble cystitis or urethritis.

A clinician may use the health history, examination, and test results to assess urinary symptoms. Tests may include urinalysis, a urine culture, or imaging.

A kidney stone may pass out of the body⁶. This movement may increase the amount of mucus in urine⁶.

A stone can also cause pain, nausea, vomiting, or blood in urine⁶. Stones that remain inside a kidney may cause no symptoms⁶.

Digestive mucus may mix with urine after both enter the toilet. In that case, the mucus did not start within the urinary tract.

Irritable bowel syndrome, called IBS, can cause mucus in the large intestine⁶. That mucus may pass during a bowel movement and then mix with urine⁶.

IBS may also cause these digestive symptoms:

Ulcerative colitis is a form of inflammatory bowel disease⁶. It can cause excess mucus that passes with stool⁶.

Other symptoms may include cramps, diarrhea, rectal bleeding, fever, fatigue, or weight loss⁶. This mucus may mix with urine inside the toilet⁶.

Mucus can occur with bladder cancer, but this is uncommon^6,7. Mucus is also unlikely to be the first sign⁶.

Blood in urine, painful urination, and frequent urination can occur with bladder cancer⁶. These symptoms can also occur with other conditions⁷. Mucus alone cannot show whether cancer is present⁷.

Persistent blood in urine requires clinical evaluation. Urinalysis may find signs linked with stones, kidney disease, or urinary cancers⁵.

Read more about testing in our guide to occult blood in urine.

A clinician may ask about painful urination and other symptoms¹⁰. Questions may also cover signs of an STI and lower urinary symptoms in males¹⁰.

Discharge and possible STI exposure can affect which causes need testing¹⁰. Past urinary problems may also help guide the assessment.

Medicines, vitamins, and supplements can affect urinalysis results. Some medicines change urine color without showing that disease is present⁵.

A physical examination may follow the health history. The findings help guide the choice of tests.

Urinalysis checks urine in several ways⁵. It may include a visual check, a dipstick, and a microscope check^4,5,8.

Each part of urinalysis provides different information:

A dipstick may check acidity, protein, sugar, blood cells, and urine concentration. The microscope can show red cells, white cells, germs, crystals, casts, and mucus⁵.

A mucus result should be read with the other findings. A large amount may lead to more tests for the cause⁴.

A clean-catch midstream sample lowers the risk of contamination. It reduces bacteria, cells, and other substances from the skin or genital area.

The collection process may include these steps:

Tell the clinician about menstruation before providing the sample⁴. Also report bleeding hemorrhoids because they can affect the sample⁴.

A urine culture grows bacteria that may be present in urine. It can help show which antibiotics may work against the bacteria.

STI testing may help when discharge or sexual exposure suggests urethritis or cervicitis¹⁰. Lasting urethritis may need added testing when the first tests are negative¹⁰.

An ultrasound uses sound waves to create images of the kidneys and bladder. It may find stones, masses, cysts, blockages, or other changes.

A CT scan uses X-rays and a computer to create detailed body images. A clinician may use imaging when stones or urinary tract changes are possible.

Cystoscopy uses a thin viewing tool to examine the urethra and bladder. It can find changes such as stones, tumors, or blockages.

Contact a clinician if the amount of mucus becomes large or keeps increasing⁶. A color or texture change also needs medical review⁶.

Arrange a medical visit when mucus occurs with these symptoms:

Older adults with a UTI may show confusion or severe tiredness. If these changes occur with urinary concerns, seek a clinical diagnosis.

UTIs can affect people of all ages. Their symptoms can resemble those of other health problems. A clinician can diagnose the cause with an examination and suitable tests.

Screening for bacteria in urine is recommended during early pregnancy. Bacteria without symptoms can raise pregnancy risks, including kidney infection and early birth.

Treatment depends on why the mucus is present. A normal amount without lasting changes may not need treatment⁷.

Clinicians treat bacterial UTIs with antibiotics. A urine culture may help guide the choice of antibiotic.

Unneeded or incorrect antibiotic use may lead to treatment failure. It can also add to resistance, which makes bacteria harder to treat.

Phenazopyridine may ease urinary pain. However, it does not treat the infection itself.

Drinking water may help wash bacteria from the urinary tract. It does not replace antibiotics when a clinician prescribes them.

Prescription antibiotics treat chlamydia and gonorrhea⁷. Over-the-counter products do not treat these infections⁷.

Sexual partners also need treatment⁶. Safer sex practices can help prevent future STI spread⁷.

Kidney stone care depends on the stone and its movement⁷. Some stones may pass with increased fluid intake⁷.

Larger stones may need shock wave treatment⁷. Very large stones may require surgery⁷.

Do not use urine color or mucus appearance for self-diagnosis. A urinalysis checks urine appearance and looks for cells, mucus, and other substances^1,5.

Home urine strips are not intended for self-diagnosis. Discuss the results with a clinician.

A small or moderate amount of mucus in urine may be normal⁴. A large amount may occur with a UTI, STI, kidney stone, or another condition⁴.

Mucus may also come from vaginal discharge, semen, cells, or stool contamination. Appearance alone cannot identify the source.

Persistent mucus with pain, fever, discharge, or blood deserves medical review. Persistent blood in urine requires clinical evaluation.

A clean-catch urinalysis can reduce contamination and show what the urine contains^3,5. Further tests can then guide care toward the actual cause.