Strong smelling urine: causes of smelly urine and what it can indicate

Most people notice unexpected changes in their bladder habits from time to time.

 

Sometimes it looks darker than usual, while other times you might find that your urine smells weird or unfamiliar. If you have recently wondered, “why does my pee smell so bad?” or what causes sudden odour shifts, it is often linked to something temporary like dehydration, diet, or medication.

The good news is that many cases of smelly urine are harmless and short-lived. Still, understanding what can influence urine smell may help you recognise when it is simply lifestyle-related and when it may need medical attention.

What Does Healthy Urine Smell Like?

Healthy urine usually has a very mild smell or almost no smell at all. The colour is typically pale yellow or straw-coloured when the body is well hydrated.

Urine can naturally smell slightly stronger first thing in the morning because it becomes more concentrated overnight. However, if the smell suddenly becomes overpowering, sweet, fishy, or chemical-like, it may be worth looking into possible causes.

Smelly Urine at a Glance: Odour Meanings

Why Does My Pee Smell? Possible Causes

There could be various reasons why the urine smells unpleasant and more intense. Below are some examples of what could cause a strong smell in urine.

Food

The smell in urine is strongly linked to what we eat. Asparagus is perhaps the most known food for giving urine a distinctly strong odour, due to the sulphurous metabolites that are excreted as it passes through the body.

 

Spicy food, such as curries, can also give urine a stronger smell. While coffee, garlic and brussels sprouts will all give urine a more distinctive odour, as they are broken down by the body when digested.

Medication

Medicines like penicillin can also affect the way urine smells, as some ingredients that go into this antibiotic are derived from mould, which can give urine a yeast-like smell. However, this is all completely harmless and should not persist once the course of medication is over.

 

Vitamin B supplements may also contribute to strong smelling urine, which may smell slightly musty. However this is not a cause for concern, and should abate if you lower your daily dosage to 10mgs or less.

 

Some people may also notice that urine smells like chemicals after starting certain vitamins or medications.

Dehydration

When you don’t drink enough water, urine becomes more concentrated – this is reflected in its colour and smell. If urine is dark in colour with a strong smell, this can indicate dehydration.

 

Highly concentrated urine, caused by low fluid intake, is often strong-smelling. When urine is too concentrated, it also irritates the bladder lining. This can cause urge symptoms, which are characterized by a frequent need to go to the toilet.

Conditions that can lead to dehydration include fever, kidney disease, diarrhoea or vomiting. Anyone can become dehydrated, but some people are more at risk, e.g. small children, the elderly or people with a chronic disease or illness. If you suspect dehydration, in yourself or in others, it’s important to act. Always make sure you, or those you care for, get enough fluids.

Strong smelling urine that is dark and cloudy can be confused with symptoms of a urinary tract infection or so-called Asymptomatic Bacteriuria (see below).

If you notice dark smelly urine, it is highly likely your body is calling for more fluids. In most cases, this concentrated odour and deep colour will improve rapidly once your hydration levels return to normal.

Bacteria

Scientists have recently found that the urinary tract has its own microflora. This means that most people have small amounts of bacteria in their urine. However, this is quite normal and doesn’t cause any discomfort.

Research is ongoing to find out the composition of this flora, whether it is stable or not and whether it can help prevent infections caused by other unwanted bacteria.

Urinary Tract Infection

Sometimes, unwanted bacteria can enter the urinary tract and cause an infection – urinary tract infection or cystitis. This is often caused by the Escherichia coli bacteria that occur naturally in the intestine, and which sometimes get into the urethra and travel up the urinary tract.

In women, a urinary or bladder infection occurs more often because the urethra is shorter and closer to the anus. In addition to bacteria, viruses or fungi can trigger an infection. The invading bacteria thrive in urine and multiply quickly and cause an infection, which can result in an unpleasant smell.

Symptoms of a urinary tract infection or cystitis can include:

• pain or a burning sensation when urinating 

• increased frequency and urge to urinate 

• traces of blood in the urine 

• dark, cloudy or strong-smelling urine 

This is one of the more common smelly urine causes that may require medical treatment.

Asymptomatic Bacteriuria

It is also possible that large numbers of bacteria can populate the urinary tract. The bacteria are usually of different types and not especially harmful. This means they can be present without causing any problems, apart from making the urine smell unpleasant.

This condition is known as Asymptomatic Bacteriuria (ASB) or ‘friendly’ bacteria. These bacteria are more common in the elderly, in women and in people with diabetes or catheters.

This condition is not usually treated with antibiotics. This is because if the balance of flora is altered, antibiotic treatment may allow other bacteria to flourish that are more difficult to deal with.

Diabetes

For people with diabetes and a blood glucose level that is too high, the kidneys pass excess sugar out through the urine. This makes the urine smell sweet.

Other symptoms of high blood sugar are feeling very thirsty and urinating frequently. If you have symptoms of high blood sugar, you should contact your doctor.

Why Does My Urine Smell Like Ammonia?

If you are noticing an ammonia scent, dehydration is usually the primary culprit. When you don’t consume enough fluids, your urine becomes highly concentrated with waste products, which naturally develops a stronger, sharp ammonia odour.

However, infections, kidney stones, and bladder irritation can also contribute to foul smelling urine with an ammonia-like smell. If the odour is persistent or accompanied by pain, it is worth seeking medical advice.

What If Urine Smells Like Fish?

When urine smells like fish, it can sometimes be linked to bacterial infections or vaginal imbalances such as bacterial vaginosis. In some cases, certain foods and supplements may also temporarily affect urine smell.

If the fishy smell continues alongside irritation, burning, or unusual discharge, it is best to get checked by a healthcare professional.

What Can Smelly Urine Indicate?

While occasional odour changes are common, ongoing or unusual smells may sometimes signal:

• dehydration 

• urinary tract infections 

• bladder irritation 

• diabetes 

• kidney stones 

• dietary triggers 

• medication side effects 

If your urine smells unusual for more than a few days or comes with other symptoms, it is important not to ignore it.

Tips on how to avoid smelly urine

Healthy skin is more resistant to infection. So, it’s essential to keep the genital area clean and healthy to maintain or improve the skin’s ability to protect itself against infection. To avoid unpleasant odours, you should not only think of how to avoid a urinary tract infection but also include a good skincare regime, e.g. using skincare products specifically designed for intimate care that keep the skin in good condition.

How to reduce the risk of a urinary tract infection

• Be extra attentive if there is any previous history of a urinary tract infection, or if a person has been assessed to be at risk 

• Drink enough fluids to stay properly hydrated 

• Try to avoid prolonged skin exposure to urine (i.e. wet incontinence products containing a lot of urine) 

• Use products with materials that keep the skin dry (e.g. by wicking away the urine into the product core to keep it away from the skin) 

• Employ toileting routines that facilitate a complete bladder and bowel emptying, since residual urine could be a risk of urinary tract infection 

• Wipe from front to back after a bowel movement, to avoid transferring bowel bacteria to the urinary tract 

• Remove products soiled with faeces immediately – from front to back 

• Avoid harsh soap sensitive areas around the genitals, as it can cause imbalance and irritation. Always choose skincare and cleansing products with a low pH (pH 4.0-6.0). This is especially important for aged and sensitive skin 

• Dry the skin gently after cleaning and before putting on a new incontinence product, since bacteria grow better in moist areas. Expose to air if possible 

• TENA Care Tip: To protect fragile or irritation-prone skin from moisture-induced odours, use specialsied formulas like TENA wash cream or wet wash gloves. Follow up with TENA barrier cream to add a soothing layer of moisture protection.

When Should You See a Doctor?

Most cases of smelly urine improve quickly once hydration, diet, or medications are adjusted. However, you should seek medical advice if you experience:

• burning or pain when urinating 

• blood in the urine 

• fever or chills 

• persistent strong odour 

• cloudy urine 

• lower abdominal pain 

If you are repeatedly asking yourself why does my urine smell so strong or why does my pee smell so bad, a medical review may help identify the cause early.

Staying Comfortable Through Bladder Changes

Changes in bladder health can sometimes come with urgency, leaks, or increased bathroom trips, especially during infections or irritation. Having reliable bladder protection nearby can help you feel more comfortable and confident throughout the day.

If bladder leaks are also part of what you’re noticing, this quick video may help you rethink what’s normal.

Explore our range of discreet incontinence products designed to support freshness, comfort, and everyday confidence whenever you need extra protection.

FAQ

Is strong smelling urine always a sign of infection?

No. Sometimes it is simply because you have not been drinking enough water, or because of something you ate earlier in the day. Infections are usually more likely when there are extra symptoms too, like burning, discomfort, or cloudy urine.

Why does my pee smell stronger in the morning?

That usually happens because urine sits in the bladder overnight and becomes more concentrated. Once you start drinking water during the day, the smell often becomes less noticeable again.

What can I drink to clean my smelly urine?

Most of the time, plain water helps the most. If dehydration is behind the smell, increasing fluids through the day can make a noticeable difference pretty quickly.

When should I worry about the smell of my urine?

If the smell changes for a short time and then goes away, it is generally not a concern. But if it keeps happening, or shows up with pain, fever, blood in the urine, or frequent urination, it is best not to ignore it.

Why does my urine smell sweet?

A sweet or fruity urine odour is often a symptom of elevated blood sugar levels (diabetes). When the body cannot process glucose efficiently, the kidneys expel the excess sugar through your urine. If you experience this alongside increased thirst or fatigue, consult a healthcare professional.

Can pregnancy cause smelly urine?

Yes, it can. Hormonal shifts, vitamins, and even mild dehydration during pregnancy may change the smell of urine. Some pregnant people also become much more sensitive to smells overall.

Can asparagus make urine smell?

Absolutely. It is one of the most common foods linked to strong-smelling urine. The effect usually does not last very long and is completely harmless.

What smell is urine when your kidneys are failing?

There is not a single smell that confirms kidney failure. Some people notice a stronger ammonia-type smell, but kidney conditions are usually identified through several symptoms and medical testing rather than odour alone.

Can a UTI cause foul-smelling urine?

Yes, it can. Many people with a UTI notice urine smelling much stronger than usual, along with symptoms like burning, pressure, or needing to pee more often.

Why Does My Urine Smell Bad But Without Pain?

That can happen more often than people realise. Food, vitamins, coffee, dehydration, and some medications may all change urine smell without causing any discomfort.

Is smelly urine a sign of cancer?

Usually, no. Most odour changes are linked to dehydration, infection, food, or medication. Even so, ongoing urinary changes are something you should always keep an eye on.

Does diabetic urine have a smell?

It can. Some people describe it as sweet or fruity because extra sugar is being passed through the urine when blood glucose levels are too high.

What does a UTI smell like?

There is no exact description everyone agrees on. Some people say it smells sour, others say musty or unusually sharp. It is often more obvious when paired with cloudy urine.

Will smelly urine go away on its own?

Often, yes. If the smell is connected to food or mild dehydration, it may settle once you hydrate properly or after the food has passed through your system. Persistent changes are worth getting checked though.

Sources:

• https://healthcare.utah.edu/healthfeed/2018/03/why-asparagus-makes-your-urine-smell
  

• https://my.clevelandclinic.org/health/diseases/16638-e-coli-infection
  

• https://www.idsociety.org/practice-guideline/asymptomatic-bacteriuria/