Why does women's urine sometimes smell like fish?: causes and treatment of trimethylaminuria disease

If your urine smells like fish, a rare metabolic disease is responsible for this, called trimethylaminuria, or shorter TMAU. With this disease, the smell of fish is not only urine, but also sweat, and air, which you exhale.

Urine smells like fish: the cause is a metabolic disease

Trimethylaminuria is a hereditary disease, in which one region of the chromosome 1 mutates.

  • When some nutrients are broken down, your body forms the metabolite trimethylamine. It is normally broken down into an odorless trimethylamine-N-oxide by further metabolic processes..
  • In trimethylaminuria, the metabolic product cannot be processed into an odorless variant. The enzymes necessary for this are not present in the body..
  • Then trimethylamine, which has a fishy odor is excreted in the urine, breath and then.
  • In addition to inherited TMAU, there is also what is known as secondary trimethylaminuria.. it may be due to cirrhosis of the liver or viral hepatitis.

Treatment of trimethylaminuria

Your doctor can make a diagnosis through a urine test. The concentration of trimethylamine is determined.

  • There is no therapy or cure for the disease.
  • However, this can be influenced by diet.. Food should be avoided whenever possible, whose ingredients are converted into trimethylamine in the body.
  • Choline is one of these substances. Choline is found in offal and egg yolks, also in avocado, corn and cabbage, eg.
  • Trimethylamine-N-oxide can also be converted back to trimethylamine by intestinal bacteria. Therefore, products with this substance should be excluded from the menu.. Trimethylamine-N-oxide is found in shellfish and fish.
  • Applying antibiotics at regular intervals, can reduce certain strains of bacteria in the gut. These products can at least reduce the odor somewhat..
  • Since victims are often socially isolated, and in some cases suffer from depression, psychological support should be part of the treatment.

The smell of rotten fish from the vagina

Less obnoxious, but also an alarming sign is a fishy smell from the vagina. If this unpleasant smell from the vagina and white discharge occurred after sexual intercourse, more likely to be candidiasis (milkmaids) or vaginosis. This condition is not associated with trimethylaminuria.

As a result of the reproduction of pathogenic bacteria, the flora of an intimate place is disturbed, which can be adjusted by taking antibiotics strictly as prescribed by the doctor.


  1. Trimethylaminuria / Genetics Home Reference, 2013—2015 (англ.) «FMO3 gene mutations account for most cases of trimethylaminuria, the condition can also be caused by other factors»
  2. S. C. Mitchell and R. L. Smith (April 2001). «Trimethylaminuria: The Fish Malodor Syndrome», Drug Metabolism and Disposition, Vol. 29, Issue 4, Part 2, 517—521, http://dmd.aspetjournals.org/cgi/content/full/29/4/517

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