Why does my pee smell and what can I do about it?

If you've ever found yourself wondering 'why does my pee smell?' in the bathroom—you're not alone. It's a commonly Googled problem, but often not one for huge concern. We spoke with experts to find out the potential reasons for urine that smells sweet, fishy, or just plain weird. 

There are a number of reasons why a strong odor can be detected in urine during a trip to the bathroom, and usually, it's pretty harmless—be it dehydration or simply something you ate. Solutions could be as simple as cutting certain foods (the main culprit being asparagus!) out of your diet, drinking more water, or trying a home health check to put your mind at rest. However, for some people, strong-smelling urine can be an early pregnancy symptom or a sign of a UTI. Knowing the common causes of smelly urine can help you determine the next steps to take—and whether you need the help of a medical professional. 

Why does my pee smell? 7 reasons for smelly urine

1. You're dehydrated

If your urine has turned a dark yellow color and started to smell, you could be dehydrated. Dr Deborah Lee, Dr Fox Online Pharmacy, advises, "Too much salt in the diet can cause dehydration, which in turn causes smelly urine. Most people have about twice as much salt every day compared to the recommended intake."

When we're dehydrated, the wee color will change from light to dark. "Mild dehydration usually changes the color of the urine from a pale yellow color similar to champagne to orange honey-type color, or even brown," explains Maya Mendoza, co-founder, and creator of PeeSting. "Strong, dehydrated urine can become quite pungent and smell like ammonia too. People are quite familiar with that smell, as ammonia is used in many household cleaning products," Maya adds. 

What to do about it

If your urine is dark and smelly due to dehydration, the solution is simple. Drink plenty of fluids, particularly water and squash, until your pee returns to a pale clear color. "It takes about three hours for what you drink to show in your urine so don't expect it to lighten up immediately," Mendoza adds. 

2. Food you're eating

Asparagus is a delicious green vegetable that comes with one very noticeable side effect—it makes your pee smell foul. According to research from the British Medical Journal, 40% of the population say they can smell 'asparagus pee' after consuming the veg. Not so pleasant when you’re using a public bathroom and someone rushes into the cubicle after you.

It’s not just asparagus that can change the scent of your urine though—sprouts, onions, garlic, curry, and even alcohol can alter the smell, too.

What to do about it 

Unfortunately, the only way to combat this particular problem is to stop consuming the culprits or come to terms with the fact you might have smelly urine after eating an asparagus dish. You could keep a diary to track your habits and then eliminate certain foods accordingly.  

3. You have a UTI

If your pee is cloudy and smelly, it hurts or burns when you pee, you have a sore vagina or you have pain in your lower abdomen, chances are you have a UTI. "Generally speaking there are some obvious changes to your urine when you have a bacterial infection (such as cystitis) in your bladder or urethra," says Mendoza.

"The depth of the changes will depend on the severity of the infection and your urological health history. The signs to look for in your pee include cloudy urine. You may notice your urine going darker or a pink color. This can mean there is blood in your pee. Often the change in color and cloudiness is accompanied by a strong—and often quite foul—smell," Mendoza adds. 

What to do about it

If you think you might have a UTI you should speak with your doctor for medical advice and start treatment as soon as possible. Depending on your consultation, your doctor may suggest drinking lots of fluids, taking painkillers, or prescribe you antibiotics. 

4. You're pregnant

Strong smelling urine is one of the early symptoms of pregnancy (as your hormones change, causing urine to become more pungent), so this could be a sign that you're expecting. "Pregnancy changes your urine and, at the beginning of pregnancy, you might find yourself needing to pee more often," Mendoza explains. "This happens because when pregnant you experience an increase of about 25% in your circulating blood, and a lot of that moves through your kidneys, which creates more urine. Sometimes at the start of pregnancy, the urine can seem brighter in color—a bit more fluorescent. This may be due to extra filtering by the kidneys and flushing out of B vitamins."

However, just because your pee smells or you're peeing more often, it doesn't automatically mean you're pregnant. There are other changes to look out for, Mendoza explains. "Other changes to urine in early pregnancy include the appearance of white particles, which is simply an increase in a normal and healthy, milky vaginal discharge called leukorrhea, which keeps your vagina moist and clean.

"Pregnancy changes and suppresses your immune system and pregnant women can become more prone to cystitis and also vaginal yeast infections. These infections can produce a discharge that can make your urine look cloudy." You could take a look at our guide to what causes thrush and the best treatments for more information. 

What to do about it

If you think you might be pregnant take a pregnancy test and speak to your doctor for further advice. If you have a negative pregnancy test, your doctor will be able to advise on other reasons why you might be experiencing changes to your urine. 

5. You're taking medication

Certain medications can change the color and smell of your urine, explains Mendoza. "Some culprits include diabetic medications that lower blood sugar by inhibiting the kidneys from reabsorbing sugar back into your blood—so you pee the sugar out." 

"Vitamin B supplements can cause fishy-smelling urine," explains Dr Lee. "This is because your body excretes excess vitamin B in the urine, which may also look bright yellow/green."

Other medications affect urine color and bring on a smell that's something like rotten eggs, including penicillin and sulfonamide antibiotics, antimalarials, and medication for rheumatoid arthritis. 

What to do about it: 

If you are concerned about how your medication is affecting your health, you should speak to your doctor for further advice. 

6. You have an STI

Dr Lee warns that smelly urine could be a sign of a sexually transmitted disease. "STIs such as chlamydia can infect the bladder as well as the cervix and genital tract. Chlamydia doesn’t have a specific smell. 

"However, gonorrhea is said to cause a mushroom-type smell from the vaginal area. A trichomonas vaginal infection is associated with a frothy vaginal discharge and a strong fishy smell."

What to do about it: 

Order an STI test online, with your doctor or a sexual health clinic to put your mind at ease and find out the next steps if you have contracted an STI.

7. You're diabetic

"It’s very common for the urine to smell strong, sweet, and ‘fruity’ in diabetes," Dr Lee told us. "UTIs are more common in diabetics and anyone with a UTI should have their urine tested to exclude diabetes. If diabetes is uncontrolled, there will also be ketones in the urine, which smell like acetone."

What to do about it: 

Book an appointment with your doctor. "The number of cases of type-2 diabetes is rising exponentially," Dr Lee explains. "This is a serious diagnosis. If you have any concerns you are strongly advised to see your doctor without delay."

When to see a doctor if you have smelly urine

Most of the time, smelly urine is totally harmless. But there are some instances where it may suggest an underlying problem.

If you are experiencing lower back pain, pain when peeing, and blood in your pee, you may have kidney stones. If your smelly pee is accompanied by jaundice, tummy pain, nausea, and vomiting, there is a chance you could be experiencing liver failure. In both instances, you should see your doctor or emergency services as soon as possible.

These things are much less common reasons for smelly urine, however, so if you notice a scent in your urine don't jump to conclusions—it's likely to be nothing to worry about.