What causes urine to have a strong odor?

Normally, urine doesn't have much of an odor. The volume and concentration of a variety of substances excreted by the kidneys can give urine an odor. Urine that is very concentrated typically has a stronger (ammonia) than usual scent, which is common for the urine, voided after waking up in the morning or if you become dehydrated during the day.
Causes of urine odor include:

  • Certain foods (e.g., asparagus due to folic acid)
  • Medications (e.g. antibiotics)
  • Vitamins (e.g., Vitamin B)
  • Infections (e.g., bladder, kidney)


  • Diabetes (uncontrolled)
  • Liver failure
  • Maple sugar urine (inherited metabolic disorder characterized by urine that smells similar to maple syrup)
  • Fistula: bowel to bladder (abnormal connection between the bowel and urinary bladder)

Sometimes it can be difficult to tell where the smell is coming from. For example, a woman may think that her urine has a strong or unpleasant odor, when actually the source is her vagina. Common vaginal infections with trichomoniasis or gardnerella, can cause strong, foul, and fishy odors. 
Pay attention to the odor of your urine. If there is a change, not simply related to dehydration (lack of fluid intake), then contact your healthcare provider.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.