What foods can cause pee to smell?

December 10, 2025 •

4 min read

According to the National Health Service (NHS), certain foods and drinks, like asparagus or coffee, are common culprits that can make your pee smell stronger. But what foods can cause pee to smell and why does this happen? The phenomenon is generally harmless and linked to the way our bodies process specific compounds found in different foods.

Quick Summary

Certain foods like asparagus, garlic, and coffee can cause a temporary, noticeable change in urine odor due to the excretion of their metabolic byproducts. The intensity is often heightened by dehydration, which concentrates waste compounds in the urine. Individual genetics also play a role in whether these smells are detectable.

Key Points

Asparagus is a common culprit: The vegetable contains asparagusic acid, which metabolizes into volatile, sulfur-containing compounds that cause a pungent odor in urine.
Genetics determine your ability to smell 'asparagus pee': Not everyone can produce or detect the characteristic sulfurous scent due to specific genetic variations.
Coffee and spices contain aromatic compounds: Chemicals like caffeol in coffee and volatile compounds in spices like curry and cumin can pass into urine, creating a distinct smell.
Dehydration concentrates odor-causing compounds: Insufficient water intake means waste products like ammonia are less diluted, resulting in a stronger, more noticeable odor.
Persistent or unusual odor may signal a health problem: While food-related smells are temporary, a long-lasting foul or sweet odor, especially with other symptoms, warrants a doctor's visit to check for conditions like UTIs or diabetes.
Hydration is the simplest solution: Drinking plenty of water is the most effective way to dilute urine and minimize or eliminate food-related odors.

How Diet Affects Urine Odor

While a mild, characteristic scent is normal, an unusually strong or different odor in urine is often directly tied to what you've consumed. The scent is the result of metabolic processes, where the body breaks down foods into chemical compounds. These compounds are filtered by the kidneys and excreted in urine. When certain substances are not fully broken down or have volatile, odorous components, they can become noticeable in the urine shortly after consumption. This is especially true for items containing sulfurous compounds or other aromatic agents.

The Infamous Case of Asparagus

Perhaps the most famous offender, asparagus, contains asparagusic acid, a compound found almost exclusively in this vegetable. When the body metabolizes this acid, it produces several sulfur-containing compounds, including methanethiol, which are then excreted. The smell is often described as pungent, rotten-like, or sulfurous. The time from consumption to noticeable odor can be as short as 15 minutes, with the scent sometimes lasting for several hours.

Interestingly, not everyone's pee smells after eating asparagus, and not everyone can detect the odor. This is due to genetic variations. Some people are 'non-producers' who lack the enzyme to create the odorous compounds, while others have a genetic mutation that causes 'anosmia,' or the inability to smell it. A large-scale study even suggested that over half of the population has asparagus anosmia.

Coffee and Caffeine

Coffee is a complex beverage that contains various compounds, including caffeol and sulfur compounds, that can affect urine odor. For many, drinking coffee results in a distinct, pungent aroma in their urine. This can be exacerbated by two factors: dehydration and caffeine itself. Caffeine is a diuretic, which means it increases urine production, and if you aren't drinking enough water alongside your coffee, your urine can become more concentrated. This intensifies the smell of the coffee's aromatic byproducts.

Other Common Food Offenders

Garlic and Onions: Like asparagus, garlic and onions contain sulfur-containing chemicals. As these are broken down by the body, the sulfur compounds can pass into the urine, giving it a strong smell often compared to rotten cabbage or eggs.
Spices and Herbs: Highly aromatic spices such as cumin, curry, and fenugreek can contain volatile compounds that are not fully metabolized. These aromatic chemicals are excreted through the urine, carrying their distinctive scent with them.
Brussels Sprouts and Cabbage: These cruciferous vegetables are also known to produce a sulfurous odor in urine, due to similar sulfur-containing compounds as garlic and onions.
Fish: Consuming large quantities of fish can sometimes result in a fishy-smelling urine. This is particularly noticeable in people with the rare genetic disorder Trimethylaminuria, where the body cannot properly break down the chemical trimethylamine.

Comparison Table: Food and Urine Odor


Food/Drink	Primary Odor-Causing Compound	Type of Odor	Duration of Odor
Asparagus	Asparagusic acid (sulfurous byproducts)	Pungent, sulfurous	Short-term (hours)
Coffee	Caffeol, other metabolites	Distinct, coffee-like	Short-term (hours)
Garlic/Onions	Sulfurous compounds	Rotten eggs/cabbage-like	Varies, can linger
Spices (Curry, Cumin)	Volatile aromatic compounds	Spicy, musky	Short-term (hours)
Brussels Sprouts	Sulfur-containing compounds	Pungent, sulfurous	Short-term (hours)

The Role of Hydration

Dehydration is one of the most common reasons for strong-smelling urine, regardless of diet. When you don't drink enough fluids, the waste products in your urine—like urea and ammonia—become more concentrated. This lack of dilution results in a more potent, ammonia-like scent. Staying well-hydrated helps dilute these compounds, making any food-related odor much less noticeable.

When to Seek Medical Advice

While changes in urine odor due to food are normal and harmless, a persistent or foul smell that doesn't go away can be a sign of an underlying medical condition. It's important to consult a healthcare professional if you experience a long-lasting, unusual odor, especially if accompanied by other symptoms.

Possible medical causes include:

Urinary Tract Infections (UTIs): A UTI can cause strong, foul-smelling urine due to bacteria buildup, often accompanied by pain, a frequent urge to urinate, and cloudy urine.
Diabetes: Uncontrolled diabetes can cause sweet-smelling or fruity-scented urine, as excess sugar is excreted.
Liver Disease: A musty smell can be an indication of liver disease, as toxins build up in the body and are released through urine.
Metabolic Disorders: Rare conditions, such as Maple Syrup Urine Disease (MSUD) or Trimethylaminuria, are caused by inherited metabolic issues that result in distinctive odors.

Conclusion

Changes in urine odor are a normal, temporary response to certain foods and beverages we consume. Asparagus, coffee, garlic, and spices are among the most common culprits, with their unique compounds being excreted after metabolism. Dehydration also plays a significant role in intensifying any smell. For most people, ensuring adequate hydration is enough to manage food-induced odors. However, if a strong or unusual smell persists, especially with additional symptoms like pain or cloudy urine, it's crucial to consult a doctor to rule out any underlying health issues. A heightened awareness of how your body reacts to different foods can be a valuable part of understanding your overall health. For further reading, explore more about the link between nutrition and urinary health with reliable sources.

Frequently Asked Questions

No, not everyone's pee smells after eating asparagus. It's determined by genetics. Some people lack the specific enzyme to produce the sulfurous compounds that cause the smell, while others have a genetic inability to detect the odor, a condition known as asparagus anosmia.

The smell from foods like asparagus is temporary and typically dissipates once the food's metabolic byproducts have been fully excreted. This process can happen quite quickly, sometimes within a few hours of consumption, though it can last up to 35 hours depending on the individual.

Yes, dehydration is a primary cause of strong-smelling urine. When you are dehydrated, your urine becomes more concentrated with waste products like ammonia, leading to a much more pungent odor.

Besides asparagus, other foods and drinks like coffee, garlic, onions, Brussels sprouts, and certain spices (e.g., cumin, curry) are known to cause temporary changes in urine odor due to their aromatic or sulfur-containing compounds.

Smelly urine that persists and is not related to diet or dehydration could indicate a health issue. You should see a doctor if you have other symptoms, such as pain during urination, cloudy or bloody urine, fever, or a sweet, fruity smell.

Yes, certain vitamin supplements can cause changes in urine odor. For example, excess B vitamins, particularly B6 and thiamin, are excreted in urine and can create a strong, sometimes fishy or musty smell.

Yes, drinking plenty of water is the simplest and most effective way to minimize food-related urine odors. Increased fluid intake dilutes the concentration of the odor-causing compounds in your urine, making the scent less noticeable.