Urine is normally diluted enough to have no odor or only a faintly noticeable odor. Changes in the odor of urine are most often related to food recently consumed, such as asparagus or spices such as garlic or curry, and is not cause for alarm. In other cases, abnormally strong, sweet, or ammonia smelling urine could indicate a medical condition.
Concentrated urine odor that resembles the common household cleaning product ammonia may suggest either a bladder retention problem or possible dehydration. Bladder retention is an inability or reduced ability to urinate. This condition can result in components in the urine, such as ammonia, becoming concentrated enough to produce a strong urine odor when they are released. Dehydration occurs when an insufficient amount of water is consumed. Water is a major component of urine, and lack of water can result in urine that has a higher concentration of waste products and a strong odor.
When urine smells normal but the smell is much stronger than usual, it is often described as pungent. Pungent urine odor can signal dehydration or a urinary tract infection, if bacteria from the infection are picked up by the urine and impart an odor to the waste. Urinary tract infections have also been known to produce foul or even musty smelling urine.
Sweet smelling urine can signal diabetes or diabetic ketoacidosis. If urine consistently has a characteristically sweet smell, a doctor should be seen to evaluate whether diabetes has developed. Diabetic ketoacidosis occurs when insulin is not properly regulated and fatty acids are broken down in place of the insulin. In this situation, the process of metabolizing the fatty acids acidifies the blood and ultimately produces sweet smelling urine.
Urine that smells like maple syrup can signal maple syrup urine disease. This hereditary metabolic disorder is caused when the body is unable to break down some protein parts, leading to a sweet urine odor. Maple syrup urine disease is treated with a special protein-free diet.
Many foods and spices can pass their characteristic odors on to the urine. Asparagus is well known to produce urine with an odd, rotten cabbage smell. Other foods, such as coffee, curry, garlic, and even some breakfast cereals, have also been known to give urine a distinct smell. These odd smells are only temporary and should dissipate after the food is digested and passed.