7 Causes of Foul Smelling Urine

Believe it or not, your pee can reveal a lot about your health. If you’re experiencing foul smelling urine, this isn’t normal and should be investigated.

To begin, healthy urine should be clear and shouldn’t have a strong odor to it. If it smells bad, or if it’s not clear, then this could be a sign of a more serious issue.

A common reason for this scary symptom is dehydration. Dehydration can cause urine to become more concentrated, resulting in a stronger smell and a darker color.

Additionally, consuming too much garlic, asparagus, coffee, or beer can cause a fishy urine smell. In this article, we’ll explore all the possibilities so that you can get some answers.

How Urine is Formed in The Body

To put simply, urine is formed in the kidneys via the filtration of blood. As the blood passes through the kidneys, various compounds are filtered out.

These compounds then exit the kidneys where they’re passed into the bladder and eventually excreted as waste.

Here’s a simplified diagram that can help you visualize the process:

Bottom Line: Waste products are filtered out of the blood via the kidneys. From here, they’re excreted as urine.


If you’re a young, healthy individual with no other symptoms then dehydration is a definite possibility for your foul smelling pee.

When you don’t drink enough water, your pee takes on a strong scent of ammonia.

This is because the urine becomes more concentrated with waste products and not enough water. If dehydration is the cause, then drinking more water should solve this.

In general, you should be drinking about 8 glasses of water per day (more if you’re doing a lot of physical activity).

Bottom Line: Without sufficient water intake, your pee will become more concentrated in waste products, leading to a bad smell.

Bladder or Urinary Tract Infection

The next possible scenario is that you’re experiencing a bladder or urinary tract infection.

These can definitely cause a fishy urine smell at times. Also, an inflammation of the bladder- also called “Cystitis”- could be to blame.

If you notice that your pee smells strong and bad, then this is a sign that you should go see your doctor.

Bottom Line: Cystitis is the official medical term for inflammation of the bladder. This could be a cause of your symptom.

You Ate Too Much Garlic and Onion

Most people don’t realize that the foods they eat have a direct effect on the smell of your pee.

If you have strange smelling urine, it could be because you’ve eaten too much garlic and/or onion. Some people won’t even find this surprising.

After all, if it smells strong going in, there’s a good chance that it’s going to smell strong coming out!

Take note of what you’ve eaten lately. Does it include a lot of garlic and onions? If so, this could be the reason why your pee smells bad.

Bottom Line: People who eat a lot of garlic or onion can experience urine that has a strange smell to it.

The Connection Between Foul Smelling Urine and Asparagus

There’s also a connection between smelly pee and asparagus. It only happens in some people’s bodies though (those who carry specific enzymes).

In some people, eating asparagus can result in pee that smells very strong. Again, look back at your diet: have you been eating a lot of asparagus?

If so, cut back and see if anything changes. If it does, then you can be pretty confident that it was, in fact, the asparagus causing your symptom.

Bottom Line: Some people have enzymes that make them susceptible to strange-smelling urine after eating asparagus.


Back before modern technology, doctors would determine if people had diabetes by tasting their urine.

As gross as it sounds, this diagnostic method is surprisingly accurate. That’s because diabetes and foul smelling urine are closely connected.

If your pee is exceptionally strong and odorous, it’s possible that you have diabetes.

Diabetes is basically when your body doesn’t produce enough insulin, resulting in increased blood sugar levels.

If you’re an older person, it’s recommended that you speak with a doctor about this symptom.

Bottom Line: Not only can diabetes cause a sweet taste in the mouth, but it can also affect your urine.

Excess Coffee Consumption

Are you a big coffee drinker? If so, this could be a cause for smelly pee. Even after coffee gets broken down by the body, it’s still able to produce a strong smell upon excretion.

In fact, sometimes pee can even smell like coffee! Keep in mind that this only happens to some people.

Cut back on coffee and see if that changes anything. If nothing changes, schedule a visit to the doctor’s office.

Bottom Line: Drinking some coffee is okay, but too much can have negative health consequences.

Intestines Leaking into Bladder

One of the more dangerous causes of smelly pee is intestines leaking into the bladder.

This is typically the result of inflammation, surgery, infection, and trauma. When this happens, the contents in the intestine mix with the contents in the bladder.

The end result is urine that smells very foul. This can also cause feces particles to appear in your urine.

People who have severe diverticulitis or Crohn’s disease are more susceptible to this than normal.

Also, certain cancers can cause this. If you have any of these preexisting conditions, it’s highly recommended that you speak with a doctor to rule out something serious.

Bottom Line: While rare, it’s possible for intestines to spill over in the bladder, leading to a bad smell in the urine.

When Should You See Your Doctor?

When should you see your doctor about your symptom? The first thing to look for are signs of a urinary tract infection (UTI).

These include a burning sensation when peeing and/or pain. If you’ve got these, go see a doctor. Most of the time, UTIs won’t get better without the proper treatment.

Also, if you have diabetes and you aren’t controlling it well, this can result in your pee smelling very strong (specifically, a strong sweet smell). So if you’ve got diabetes, go see a doctor.

Bottom Line: If you have a UTI, an antibiotic treatment will be required. A burning sensation when peeing is another common symptom to look for.

Most Cases Aren’t Life-Threatening

The good news is that most cases of foul smelling urine are benign. This is especially true if it’s your only symptom.

Now if your symptoms are associated with more serious ones like pain or burning when peeing, then you should look more into it.

But if smelly pee is all you’re experiencing, you’re probably okay. As always, you should speak with a doctor for a more precise answer.

The best thing you can do today is start drinking more water. If you’re not drinking at least 8 glasses of water per day, chances are good that your pee is too concentrated, which is resulting in a foul smell.

Ask a Question: If you want to ask a medical doctor a question that hasn't been answered in one of our articles go to: Ask a Medical Doctor About your Symptoms

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