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
• Kidney stones (Hard objects that form inside the kidneys and are made of chemicals in urine.)
• 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)

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.

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.