Why Your Urine Smells Bad: Understanding the Causes

Ever notice a sudden change in how your urine looks or smells? You're not alone. While it’s not the most glamorous topic, urine can actually reveal a lot about your health, from hydration levels to possible infections. In this article, we’ll break down what’s normal, what’s not, and when it might be time to talk to your doctor about changes in your pee’s color or scent.

What Does Normal Urine Look & Smell Like? 

The kidneys filter blood to remove waste products from the body in the form of urine (pee). Human urine is 95% water. The remaining 5% consists of waste products, including urea, ammonia, creatinine, and uric acid, as well as excess electrolytes such as sodium, potassium, calcium, and chloride.

Normal urine is yellowish in color (it can range from clear to pale yellow). Fresh urine is typically odorless, but it may have a mild odor depending on the individual's diet. 

What Can Cause Foul-Smelling Urine?

1. Dehydration 

Not drinking enough water is a common cause of abnormal urine odor. When you’re dehydrated, your body tries to retain as much water as possible, resulting in concentrated urine. Consequently, the natural waste product ammonia is less diluted, causing a more intense smell. 

2. Diet choices

Certain foods can cause your urine to have an unpleasant odor. For example, eating asparagus can give your urine a sulfur-like smell because of a substance called asparagusic acid. Other foods that can give your pee a more pungent smell, including pee that smells like ammonia or sulfur, include:

• Seafood

• Onions

• Garlic

• Brussels sprouts

• Cauliflower 

• Cabbage

• Coriander

• Cumin

• Coffee

• Alcohol

3. Health conditions

Certain medical conditions can cause strong-smelling urine, for example:

• Urinary tract infections (UTIs) (ammonia smell)

• Kidney stones and other kidney diseases

• Bladder infection (cystitis)

• Kidney infection (pyelonephritis)

• Prostate infection

• Yeast infections, such as bacterial vaginosis 

• Sexually transmitted infections such as chlamydia

• Liver disease

• High blood sugar or uncontrolled diabetes (sweet-smelling urine)

• Diabetic ketoacidosis (fruity-smelling urine)

• Menopause

• Fistula (abnormal connection between the gastrointestinal tract and bladder)

• Metabolic disorders

• Trimethylaminuria (fishy-smelling urine)

• Phenylketonuria (musty odor)

• Maple syrup urine disease (sweet smell)

4. Medications and supplements

Taking medications and dietary supplements can cause your urine to smell stronger. For example, sulfonamide antibiotics, diabetes medication, phenazopyridine, medicines used to treat rheumatoid arthritis, and B vitamin complexes such as thiamine and choline.

5. Early pregnancy

There can be changes in the smell of your urine if you’re pregnant due to:

• Hormonal changes, especially during early pregnancy

• Dehydration due to a lack of sufficient water intake

• Use of supplements such as prenatal vitamins

• Heightened sense of smell during pregnancy

Signs That Your Urine Odor May Not Be Normal

Three changes that can occur in urine that might indicate that your urine is not normal include:

• Changes in color (darker yellow, orange, pink, red, or dark brown)

• Changes in urine smell (sulfur smell, fishy smell, or sweet-smelling urine)

• Changes in appearance (foaming, frothing, cloudy urine, blood in urine)

Some of these changes are temporary and harmless, while others may indicate a more serious medical condition.

Other symptoms accompanying bad-smelling urine

There’s usually a simple explanation for urine that smells a little different. In most cases, the smell disappears within a day or two. You don’t have to worry if you have smelly urine, especially if it isn’t accompanied by any other symptoms.

However, if the foul smell of urine persists and you experience additional symptoms, you should consult your healthcare provider. Symptoms you should not ignore include:

• Pain or burning sensation with urination

• Frequency or urgency of urination

• Vaginal or penile discharge

• Abdominal pain

• Back or flank pain

• Fever, chills, nausea, and other signs of infection

How to Get Rid of Bad-Smelling Urine 

Bad-smelling urine often goes away on its own, especially if it's caused by something harmless like dehydration, certain foods (like asparagus), or vitamins. However, if the odor persists or is accompanied by other symptoms, it could indicate an infection or other medical issue that may require treatment. 

It’s important to have unusually smelling pee, such as urine with a fish odor, evaluated by a healthcare professional. If your doctor has ruled out underlying health conditions, the following tips may help prevent smelly urine:

• Drink enough fluids. The goal should be to drink plenty of water to stay hydrated. Avoid fizzy drinks, sugary beverages, coffee, and alcohol.

• Avoid eating foods such as asparagus and garlic that contain chemicals that can cause smelly urine.

• Avoid taking dietary supplements without consulting your doctor. Certain supplements, like vitamin B6, can change the smell of your urine.

• Maintain good personal hygiene in the genital area.