Urine Odor -

Urine has an odor. It’s often mild and hard to notice. Certain conditions, however, can cause urine to smell different. The odor might cause worry about a problem or illness.

Causes
When to see a doctor

Urine is made up mostly of water. But it also has waste in it that comes from the kidneys. What is in the waste and how much there is causes urine odor.

Urine with a lot of water and little waste has little to no odor. If urine has a lot of waste with little water, also called concentrated, it might have a strong odor from a gas called ammonia.

Some foods and medicines, such as asparagus or certain vitamins, can cause urine odor, even in small amounts. Sometimes, urine odor points to a medical condition or disease, such as:

Bacterial vaginosis (irritation of the vagina)
Bladder infection
Cystitis (irritation of the bladder)
Dehydration — when the body doesn’t have enough water and other fluids to work as it should.
Diabetic ketoacidosis (in which the body has high levels of blood acids called ketones)
Gastrointestinal-bladder fistula (an unusual link between the intestines and the bladder)
Kidney infection — which can affect one or both kidneys.
Kidney stones — or hard objects made of minerals and salts that form in the kidneys.
Maple syrup urine disease (a rare condition passed through families, called genetic, that shows up in infancy)
Metabolic disorder (a problem with how the body changes the food into energy)
Phenylketonuria (PKU) (a rare condition passed through families, called genetic, that involves a buildup of a certain amino acid in the body)
Type 2 diabetes (if it’s not controlled)
Urinary tract infection (UTI)

Most changes in urine odor are temporary and don’t mean you have a serious illness, particularly if you have no other symptoms. When an unusual urine odor is caused by an underlying medical condition, there are other symptoms too. If you’re concerned about the odor of your urine, talk to your doctor.

References

Feehally J, et al. eds. Urinalysis. In: Comprehensive Clinical Nephrology. 6th ed. Elsevier; 2019. https://www.clinicalkey.com. Accessed April 11, 2023.
McPherson RA, et al., eds. Basic examination of urine. In: Henry’s Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed April 11, 2023.
Symptoms & causes of kidney infection (pyelonephritis). National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-infection-pyelonephritis/symptoms-causes. Accessed April 11, 2023.
Bacterial vaginosis (BV). Centers for Disease Control and Prevention. https://www.cdc.gov/std/bv/stdfact-bacterial-vaginosis.htm. Accessed April 11, 2023.
Smelly urine. National Health Service. https://www.nhs.uk/conditions/smelly-urine/#:~:text=If%20you%20have%20other%20symptoms,2%20diabetes%20or%20kidney%20stones. Accessed April 11, 2023.
Gupta K. Acute simple cystitis in females. https://uptodate.com/contents/search. Accessed April 12, 2023.