9 Causes of Smelly Urine—and What To Do About It

Asparagus isn't the only thing that can change the smell of your pee. Here are 9 causes of smelly urine.

Like urine color, the smell of your urine can be a clue about your body's condition. Smelly urine can be caused by dehydration, certain foods, coffee, various infections (e.g., yeast infections), kidney stones, diabetes, and vitamins. Learn more about these causes and what you can do about smelly urine.

Dehydration

Not drinking enough water is the top cause of smelly urine, Sonita Dutta, MD, urogynecologist at NorthShore University HealthSystem in Illinois, told Health. This is because urine is a combination of water and waste products. "So when you're dehydrated, your urine has less water in relation to waste products, which can make you have smelly urine," Dr. Dutta said.

You can check the color of your urine to confirm whether you're dehydrated. If it's amber- or honey-colored, or even a dark orange, you probably need to up your water intake. But if it's a pale straw or transparent yellow color, you're well hydrated, which means your urine could be smelly for another reason.

Eating Certain Foods

Asparagus is notorious for making urine smelly. But it can also be normal if eating this vegetable doesn't change the smell of your pee. According to Dr. Dutta, everyone digests food differently, and some can get away with eating asparagus without any change in their urine. "It's most likely because their body doesn't have the enzyme they need to break it down completely," Dr. Dutta explained. But others do have the enzyme, and when those people digest asparagus, "their bodies make something called a sulfur metabolite, which can make the urine have a sulfur or ammonia smell."

Other foods, like Brussels sprouts, onions, garlic, curry, salmon, and alcohol, can have similar effects. Dr. Dutta suggested drinking plenty of water when eating foods that you know change the smell of your pee—it'll dilute your urine so the stench isn't so noticeable.

Drinking Coffee

Coffee is another food that could change the odor of your pee. Coffee metabolites, or the byproducts that come from coffee when it's broken down in your body, can make urine smell, Dr. Dutta said. Again, this does not occur for everyone. If you have never had smelly pee after drinking coffee before, this likely is not the cause.

Coffee is also a diuretic, meaning it makes you have to pee a lot. Diuretics can cause dehydration, so on top of the smell from those coffee metabolites, your pee may also have a stench because it's more concentrated than usual. To prevent dehydration, you can try drinking more water before your coffee.

Urinary Tract Infection

A urinary tract infection (UTI) occurs when bacteria get into your urinary system through the urethra and then begin to multiply in the bladder. These bacteria can make your pee smell bad.

However, according to Dr. Dutta, you will likely have other symptoms if you have a UTI. You may have to pee more frequently, experience a burning sensation when peeing, and even have cloudy or bloody urine.

Yeast Infection

Yeast is a microorganism that naturally lives in various parts of the body, including the vagina. But when yeast grows out of control, it can trigger an infection. Yeast infections occur in the vagina, but because the urethra is so close to the vaginal opening, your urine may pick up a scent from the neighboring infection, Dr. Dutta said. But like a UTI, a yeast infection usually comes with other symptoms. These can include itching, redness, swelling of the vagina and vulva, and thick white discharge.

Sexually Transmitted Infection

"Some STIs may cause urethritis, or inflammation of the urethra," Dr. Dutta said. "Anything that causes inflammation or irritation can potentially be associated with bacteria or pus or bleeding, which can change the smell of the urine." Chlamydia, trichomoniasis, and gonorrhea are the STIs that most commonly cause urethritis. But even if an STI doesn't cause urethritis, urine could still pick up a smell from irritation in the vagina, Dr. Dutta added.

If you think you have an STI, meet with your healthcare provider. They can test you and help you determine the best option for treatment.

Kidney Stones

Kidney stones can also affect your urine. They develop when salt and other minerals found in urine stick together and form hard stone-like deposits that can be as small as sand-like grains or as large as full-on chunks of gravel. "Kidney stones can collect bacteria and lead to infection or sometimes bleeding," Dr. Dutta said. "That can then change what the urine smells like."

Other symptoms of kidney stones include back, side, or groin pain; nausea or vomiting; frequent urination; blood in your urine; pain with urination; and fever. "Kidney stones are never, ever going to just be smelly urine," Dr. Dutta added. "There will be other symptoms, as well."

Some kidney stones pass in the urine without any need for treatment. However, seek medical attention if you have severe pain, vomiting, bleeding, signs of infection, or a fever higher than 100.4 F.

Diabetes

People who have undiagnosed diabetes are "spilling out sugar into their urine," Dr. Dutta said. That's because they can't process sugar the way most people can, meaning they have excess glucose in the blood, which the body tries to get rid of through pee. "When you have that extra sugar in your urine, it's going to give it a sweet, fruity smell," Dr. Dutta explained. People with uncontrolled diabetes will likely also have increased pee urgency or frequency, as the sugar irritates the bladder.

If you think you might have diabetes, meet with your healthcare provider as soon as possible.

Vitamins

According to Dr. Dutta, many people notice their urine smells different after taking vitamins—the same way some people detect a different urine odor after eating certain foods. But there's nothing to worry about if you conclude a vitamin is making your pee smell. "Vitamins tend to be a little bit in excess of what your body truly needs, so you'll often end up peeing some of that out," Dr. Dutta said.

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