What Causes Abnormal Urine Odor?

Conditions list medically reviewed by George Krucik, MD, MBA

Urine naturally has an odor that is unique to everyone. Urine doesn’t usually have a strong odor. You may notice that your urine occasionally has a stronger smell than it normally does. This isn’t always a cause for concern. Sometimes strong or... Read More

Urine naturally has an odor that is unique to everyone. Urine doesn’t usually have a strong odor. You may notice that your urine occasionally has a stronger smell than it normally does. This isn’t always a cause for concern. Sometimes strong or unusual smelling urine is a sign of an underlying medical problem.

When to see a doctor

Make an appointment with your doctor if you have a strong or abnormal urine odor that lasts for more than two days. If you have symptoms such as:

  • sweet-smelling urine
  • mental confusion
  • bloating
  • nausea
  • vomiting

These symptoms may be signs of diabetes, severe dehydration, or liver disease.

Asparagus and urine odor

One food that many people say makes their urine smell strong is asparagus. The culprit of urine odor from asparagus is caused by the level of naturally occurring sulfurous compounds that it contains. This compound is called asparagusic acid. While it doesn’t harm the body in any way, it does create a strong, odd smell after you eat something that contains it — such as asparagus.

Some don’t notice a change in the way their urine smells. It’s possible that your genetics determine if asparagus makes your urine smell strong.

If your body does produce the odor, it will go away after the asparagus has passed through your system. You should contact your doctor to check for other causes if the odor does not go away after 12 hours.

In pregnant women

During pregnancy women have an increase in a pregnancy hormone called hCG. This increase can cause your urine to have a strong odor. This is especially true in early pregnancy. However, women also have a heightened sense of smell during pregnancy which could contribute to any strong urine odor they report.

Pregnant women also need to drink more water to keep from being dehydrated. Dehydration causes uric acid to build up and creates a strong odor in the urine.

Underlying medical causes of urine odor

Several conditions can cause strong or unusual urine odor. The most common causes include:

Dehydration

Dehydration occurs when you don’t drink enough fluids. If you’re dehydrated, you may notice that your urine is a dark yellow or orange color and smells like ammonia.

Most people only experience minor dehydration and don’t require medical treatment. Drinking more fluids, especially water, will generally cause urine odor to return to normal. Alcohol and coffee are both diuretics, which means they make you urinate more often.

If you are experiencing mental confusion, weakness, extreme fatigue, or other unusual symptoms, you may have severe dehydration and should get medical treatment right away.

Urinary tract infections

Urinary tract infections — often called UTIs — commonly cause urine to smell strong. A strong urge to urinate and a burning sensation upon urination are the most common symptoms of a UTI. Bacteria in your urine cause urinary tract infections. If your doctor determines you have a UTI, they’ll give you antibiotics to kill the bacteria.

Diabetes

A common symptom of diabetes is sweet-smelling urine. People with untreated diabetes have high blood sugar levels. High blood sugar levels cause the sweet urine odor. See your doctor as soon as possible if your urine frequently smells sweet. Untreated diabetes is dangerous and can be life threatening.

Bladder fistula

A bladder fistula occurs when you have an injury or defect that allows bacteria from your intestines to enter your bladder. Bladder fistulas can occur due to surgical injuries or bowel diseases such as inflammatory bowel disease, ulcerative colitis, or Crohn’s disease.

Liver disease

A strong urine odor can be a sign of liver disease. Other symptoms of liver disease include:

  • nausea
  • vomiting
  • abdominal pain
  • yellow skin or eyes, called jaundice
  • weakness
  • bloating
  • weight loss

See your doctor right away if you have symptoms of liver disease. Untreated liver disease can be life threatening.

Phenylketonuria

Phenylketonuria is an incurable genetic disease that is present at birth. The disease makes you unable to break down an amino acid called phenylalanine. When these metabolites accumulate your urine may develop a “mousey” smell. Other symptoms include:

  • decreased skin pigmentation
  • mental defects
  • slow-developing social skills

If this disease is not treated early, it can lead to ADHD and severe mental handicaps.

Maple sugar urine disease

Maple sugar urine disease is a rare and incurable genetic disease that causes urine to smell like maple syrup. People with the disease can’t break down the amino acids leucine, isoleucine, and valine. Lack of treatment can lead to brain damage and death.

Diagnosis

To determine if your urine odor is caused by a medical condition, your doctor will use several tests. Some of these are:

  • Urine analysis: A sample of your urine is tested for signs of certain types of bacteria as well as other elements, and may also do a bacteria culture of your sample.
  • Cystoscopy: A thin tube with a camera on the end is inserted into your bladder to look for any urinary disease.
  • Scans or imaging: This isn’t used very often with urine odor. But if the odor persists longer than 12 hours and there isn’t any sign of infection from the urine analysis, your doctor may choose to take x-rays or ultrasound.

Healthy urination habits

The following are some good habits to keep your bladder healthy.

  • urinate five to seven times per day — if you aren’t then you need to drink more water
  • you should only need to get up one time at night while sleeping
  • only urinate when you really need to — not just in case except before bedtime because forced urination trains your bladder to hold less.
  • sit down, instead of hovering over the toilet while urinating
  • take your time and don’t push to get it out faster

Outlook

Urine odor can be caused by numerous reasons; what you ate the night before or the side effect of some medications. However, if the odor is new and doesn’t go away after 12 hours, you should check with your doctor to rule out a medical conditions.

Medically reviewed by University of Illinois-Chicago, College of Medicine on January 26, 2017Written by Rose Kivi and Diana Wells


5 possible conditions

This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.