Dehydration and concentrated urine are the primary causes of dark urine, according to Healthline. Other causes include gallstones, jaundice, liver disease and kidney cancer. Causes of smelly urine include diabetes, urinary tract infections and bladder fistula.
A pigment called urochrome gives urine its yellow color, reports WebMD. The urine color usually changes with its concentration, and darker urine may indicate that a person is not drinking enough fluid. Circulation of unusual and excess waste products may also cause dark urine, which may result from the presence of bile products due to liver disease.
Urinary tract infections, caused by bacteria in the urine, may cause an urge to urinate, a burning sensation when urinating and strong-smelling urine, notes Healthline. High blood sugar levels, a condition common to people with diabetes, may cause sweet-smelling urine. A defect or injury from surgery or conditions such Crohn’s disease or ulcerative colitis can allow bacteria from the intestines to enter the bladder, causing smelly urine. Additionally, eating asparagus can change urine smell, due to the breakdown of methyl mercaptan, which is a sulfur compound also found in garlic.
Patients should see their doctor in the event of changes in the color or smell of their urine, stresses Healthline. Treatment for dark urine includes a physical examination and urinalysis and depends on the symptoms, medical history and results of laboratory studies.