The kidneys produce urine, and the urinary system helps the body to remove waste and regulate the volume and composition of blood. The waste that comes out in urine can affect its color and odor.
The most common reason for a person's urine to smell like coffee is that they have simply drunk too much coffee.
In this article, we look at why this occurs. We also describe other possible causes of urine that smells like coffee and several ways to get rid of the odor.
If someone drinks a lot of coffee, their urine may contain enough chemical compounds to make it smell like coffee.
Urine is mostly water, so healthy urine should be pale and usually odorless. Waste products give urine its color, smell, and appearance. These products may include:
- digested, or metabolized, material from food and drinks
- toxins or allergens that a person has breathed in
- hormones and other bodily chemicals
- drugs or medications
Below are some reasons that urine may smell like coffee:
Drinking too much coffee
Coffee contains more than 1,000 chemical compounds that contribute to its flavor, smell, and appearance. Antioxidants called polyphenols are primarily responsible for the smell of coffee.
The polyphenols in coffee are absorbed by the digestive tract and put to use, then broken down and excreted in urine. So, if someone drinks a lot of coffee, their urine may contain a high enough concentration of polyphenols and other coffee compounds. This will make it smell like coffee.
Coffee also contains a stimulant, caffeine, which increases the rate of urination and can lead to dehydration. When a person is dehydrated their urine is more concentrated, so it contains less water and more waste products than usual.
It is possible to overdose on caffeine, though this is rare. The following symptoms may indicate that a person has overdosed and should seek medical advice:
- confusion or disorientation
- chronic insomnia
- chronic headaches
- chest pains
- an irregular or fast heartbeat
- difficulty breathing
When the body is dehydrated, urine becomes more concentrated. It will smell stronger and appear darker than healthy urine, which is pale or clear.
If someone becomes dehydrated after drinking too much coffee, or if they drink coffee while otherwise dehydrated, their urine will often smell like coffee.
Certain foods and drinks
Several foods and beverages cause the urine to have an unusual smell or appearance. These odors can have varied characteristics, and conditions like the common cold and pregnancy can affect a person's sense of smell.
Foods that change the smell of urine include:
- leafy greens, especially kale
- puffed wheat
- spicy foods that contain capsaicin, an active compound in chili peppers
No potentially severe health conditions, except dehydration, are associated with urine that smells like coffee.
However, people interpret smells differently. It may be easy to mistake a smell that indicates a problem for the smell of coffee, which is often more familiar.
The following medical conditions can cause changes in the odor of urine, or an altered sense of smell:
- nasal congestion
- a burnt tongue or mouthinflammation or infection of the bladder or urinary tract can cause urine to smell strong or foul
- metabolic and liver disorders are associated with musty-smelling urine
- kidney failure and disease are associated with dark, stronger-smelling urine
- uncontrolled or untreated type 2 diabetes is associated with sweet-smelling or pungent urine
- maple syrup urine disease causes urine to smell very sweet, similar to burnt caramel
- bladder fistulas are associated with urine that smells like feces or gas
Urine odor and pregnancy
A woman's urine can smell different during pregnancy, and this is often caused by urinary tract infections (UTIs).
Women often report that their urine smells differently at various stages of pregnancy. This may be caused by frequent urinary tract infections (UTIs), hormonal changes, or dehydration.
Below is more information on why urine can smell different during pregnancy:
Many pregnant women develop infections in the bladder or urinary tract during pregnancy, and these can lead to strong- or foul-smelling urine.
UTIs are especially common in weeks 6 to 24 of pregnancy.
Many women with UTIs also notice:
- cloudy urine
- more frequent urination
- pain or cramps in the lower abdomen
- pain and burning when urinating
The bacteria involved in UTIs can spread to the kidneys and other pelvic organs if left untreated. Pregnant women who experience lower back pain, nausea, vomiting, chills, or a fever should seek medical attention and treatment.
Human chorionic gonadotrophin (hCG)
During the first few weeks of pregnancy, the levels of the hormone hCG in a person's blood rise rapidly. Many people report that this changes the smell of their urine.
Heightened sense of smell
Some research has shown that people tend to have a heightened sense of smell during their first trimester of pregnancy. A person may notice the smell of waste products in their urine, including byproducts of coffee, more than usual.
The kidneys and bladder also change during pregnancy. The kidneys work 50 percent harder, and this causes a person to urinate more often, making it easier for them to become dehydrated.
Many pregnant people also experience altered kidney function. This involves an increased number of nutrients and electrolytes being excreted in the urine, which can alter the smell.
The best way to eliminate the smell of coffee in urine depends on the cause. Often the most effective way to do so is to reduce coffee consumption.
People who drink more than 4 cups of coffee a day are more likely to excrete the compounds in the drink without absorbing them. For these people it is a good idea to drink more water, to balance the intake of caffeine.
If other foods or drinks are affecting the smell of urine, it is a good idea to avoid or limit consumption.
If an underlying medical condition may be causing the smell, seek medical treatment.
It is not uncommon for urine to smell like coffee if a person has drunk too much coffee or had any while dehydrated.
Some conditions, such as uncontrolled type 2 diabetes and bladder infections, can give urine an odor that may be mistaken for coffee.
Consult a doctor if urine that smells like coffee is accompanied by:
- pain, burning, or discharge when urinating
- an increase in the urge to urinate
- a reduced rate of urination
- swelling and pain in the lower abdomen
- pain in the lower back
- nausea, vomiting, and diarrhea
- fever or chills
- flu-like symptoms that last longer than two weeks
If a person suspects that their diet is not responsible for foul- or very strong-smelling urine, it is a good idea to speak with a doctor.
While rare, it is possible to overdose on caffeine. Too much caffeine can make a person shaky, restless, and anxious. Seek medical attention for symptoms of severe caffeine overdoses.