Foamy urine is the presence of a white froth or bubbly lather in the toilet bowl after urinating. It is a common sign of proteinuria (protein in the urine).  It can frequently occur for less innocuous reasons and may be transient with no other episode occurring again for weeks or months.

What Causes Foamy Urine?

Questions to Ask if Urine is Foamy

  • Has a detergent been added to the toilet water? Toilet sanitizers added to the cistern (tank) water may cause frothy water and once these bubbles settle, any agitation will cause the bubbles to form again. Recently cleaned toilet bowls may still have remnants of soapy detergents.
  • Is your urine flow forceful? Straining or pushing out the urine with force can cause bubbling of the water. Urinating ‘loudly’ may be a sign of forceful urination. Gravity also plays a part in the force of the urine striking the water in the toilet bowl.
  • Has the toilet bowl been flushed? The presence of another person’s urine, probably with protein in their urine, may cause bubbling on subsequent use if the toilet has not been flushed.
  • Have you recently had sexual intercourse or been sexually stimulated? In men, the presence of semen remaining in the urethra could cause foamy urine although under usual circumstances, the quantity of remaining semen is too little. However, retrograde ejaculation where semen enters the bladder is a possible cause of foamy urine. In women, foamy urine due to the presence of vaginal discharge is less likely.


To clearly identify foamy urine rather than bubbles caused by some other substance tainting the toilet water or due to force, it is advisable to urinate in a sterile container.  Inspect the urine to identify foam or ‘head’ (similar to a beer). The presence of other substances that may act as surfactants and reduce the surface tension of urine should also be considered.

The quantity of protein in the urine is also a consideration. There may be certain conditions that cause a slight increase in the quantity of protein in the urine, which is temporary. This includes :

  • Strenuous exercise
  • Fever – the cause of the fever should be investigated and treated.
  • Severe cold or heat exposure (environmental).
  • Emotional stress.
  • Certain drugs.

There may be other harmless causes of foamy urine but this should be discussed with a doctor to exclude more serious conditions. A small amount of protein in the urine, less than 150mg/day, is normal. However, the presence of albumin (the most common type of protein in the blood) is a cause for concern as it indicates glomerular damage (damage to the filtering ‘apparatus’ of the kidney). This can be confirmed by a urine dipstick test or sending a urine sample to a laboratory for urinalysis.

Other Causes

Some of the causes of proteinuria include :

  • Amyloidosis.
  • Cancer.
  • Chemical, heavy metal poisoning.
  • Diabetes.
  • Envenoming – venom from snake/insect bite or sting.
  • Heart conditions – enlargement, inflammation or failure.
  • Hypertension (high blood pressure).
  • Infections, particularly those of the urinary tract (UTI), although other systemic and localized infections can lead to proteinuria (fever).
  • Kidney failure.
  • Liver disease, damage or failure.
  • Lupus (SLE) and other types of autoimmune diseases.
  • Pregnancy.
  • Renal vessel conditions like renal artery stenosis.
  • Rheumatoid arthritis.
  • Sarcoidosis.
  • Sickle cell anemia.

Article reviewed by Dr. Greg. Last updated on June 4, 2010