Normal urine has a clear yellow color and a slight ammonia smell. Urine forms when your kidneys filter excess water from your bloodstream, along with waste byproducts. As red blood cells age, hemoglobin in the cells breaks down and forms a yellow compound called urochrome, giving urine its yellow tint. Some compounds in foods and medicines temporarily give urine unusual colors and odors. Most urine odors mark changes in diet but not changes in health.
Not all foods pass odors along to your urine. Foods that do include asparagus, coffee and some spices. Asparagus, one of the worst offenders, gives the urine of most people a foul, sulfurous stench. Not everyone who eats asparagus experiences the same effects, leading researchers to suspect that either some people can't smell the compounds or not all people produce the smell. If the odor of your urine corresponds to the smell of food you recently ate, in most cases you shouldn't worry. Some specific odors could indicate medical problems.
If your pancreas works properly, sugar in the blood triggers a flood of insulin needed to process the fuel. In diabetics, insufficient insulin causes blood sugar to rise. Excess sugar gives your urine a sweet smell. Urine that smells like maple sugar could mark a rare genetic disorder called maple sugar urine disease. Victims of MSUD lack the enzymes needed for breaking down some amino acids. The unusable amino acids leave the body through the urine, giving it a maple sugar odor. MSUD usually manifests in infancy. If you're an adult in good health, you're not at risk, but if the disease runs in your family, you could carry the gene responsible for the condition.
Some medications such as antibiotics might add odd odors and strange colors to urine. If you're taking prescription medicine and note unusual urine qualities, ask your doctor whether the drug causes these side effects. B-complex vitamins give urine a harmless, odd smell and a surprising yellowish-green murky color. Foods such as beets and blackberries temporarily color your urine. Dark urine in any shade of red or purple, unrelated to food, might signal internal bleeding from a urinary infection. Bad odors sometimes accompany these problems, along with pain in the lower back or painful urination. Liver disease could give your urine an unusual musty odor.
If you don't drink enough water, your urine could acquire a cloudy yellow color and an ammonia smell. Waste products concentrate in the urine as your body dehydrates and excretes less water. When you drink enough water -- about eight glasses a day in normal conditions -- your urine appears light yellow and clear, with less ammonia odor. If you notice the smell of feces when you urinate, this could mark a serious internal disorder called diverticulosis. Abnormal pouches forming on the walls of your intestines could connect to your bladder through a growth called a fistula. Report any consistent changes in urine color and odor to your doctor.