SymptomKidneys & urinary tract
Unusual Color or Odor to Urine
Unusual urine color or odor is usually harmless. Foods (beets, asparagus), vitamins, medicines and how much you drink change urine within hours. But some changes point to a problem: cloudy, foul-smelling urine with burning suggests a urinary tract infection; red or pink urine can mean blood; foamy urine can mean protein leaking from the kidneys; and a sweet or fruity smell can be a sign of uncontrolled diabetes. Changes that last more than a day or two without an obvious cause should be checked.
Also called: Abnormal urine color, urine discoloration, foul-smelling urine, malodorous urine, strong-smelling urine
At a glance
- Normal urine
- Pale straw to amber, with a mild smell.
- Usually harmless causes
- Hydration level, foods, vitamins, medicines.
- Infection clues
- Cloudy, foul-smelling urine with burning, frequency or urgency.
- Kidney and metabolic clues
- Persistent foam (protein), sweet or fruity smell (diabetes), brown urine (liver or muscle).
- Diagnosis
- Urine dipstick, microscopy and culture, plus blood tests if needed.
When to get help
Call 911 or go to the ER
- Sweet or fruity-smelling breath or urine with vomiting, abdominal pain, fast breathing or confusion (possible diabetic ketoacidosis)
- Very little or no urine for 12 hours with dizziness or confusion
- Cola-colored urine with severe muscle pain after extreme exercise or injury
See a doctor within a day or two
- Red or pink urine, or passing clots, that is not explained by food
- Cloudy, smelly urine with fever, back or side pain, or vomiting
- Brown urine with yellow skin or eyes
- Urine changes with swelling of the legs, face or around the eyes
Book a routine appointment
- Urine that is persistently foamy or bubbly
- Strong-smelling or cloudy urine that lasts more than 2 days despite drinking more
- Recurrent urine infections
Usually safe to manage at home
- Bright yellow urine after taking B vitamins
- Strong smell after eating asparagus or when you have not drunk much
- Pink or red urine within a day of eating beets, with no other symptoms
Urine color chart
| Color | Common harmless causes | Medical causes |
|---|---|---|
| Clear | Drinking a lot of water | Diabetes insipidus, diuretics |
| Pale to dark yellow | Normal hydration range | Dehydration if dark |
| Bright neon yellow | B vitamins (riboflavin) | None |
| Orange | Carrots, rifampin, phenazopyridine | Dehydration, liver or bile duct problems |
| Red or pink | Beets, blackberries, rhubarb, some medicines | Blood (infection, stones, cancer), muscle breakdown |
| Brown or cola | Fava beans, some medicines | Liver disease, rhabdomyolysis, kidney inflammation |
| Green or blue | Food dyes, amitriptyline, propofol, methylene blue | Pseudomonas infection (rare) |
| Purple (in catheter bags) | None | Purple urine bag syndrome from bacteria in long-term catheters |
| Cloudy or milky | Phosphate crystals after a meal | Infection, pus, kidney stones, rarely lymph fluid |
For deep yellow, amber and brown urine, see dark urine. For red or pink urine, see blood in urine.
Cloudy urine
Cloudy urine is most often caused by:
- Urinary tract infection: cloudy, smelly urine with burning, frequency, urgency and lower belly discomfort.
- Dehydration: concentrated urine can look cloudy.
- Crystals: harmless phosphate crystals, especially after a large meal or dairy, or crystals linked to kidney stones.
- Vaginal discharge mixing with urine.
- Sexually transmitted infections such as chlamydia or gonorrhea.
- Prostatitis in men.
Foamy or bubbly urine
Some bubbles are normal, especially with a strong stream. Foam that persists in the toilet bowl, especially every time, can mean proteinuria, protein leaking through damaged kidney filters. Causes include diabetes, high blood pressure, and kidney diseases such as nephrotic syndrome, which also causes swelling of the legs and around the eyes. A simple urine test for protein (albumin-to-creatinine ratio) checks this.
Urine odor: what different smells mean
| Smell | Possible cause |
|---|---|
| Strong ammonia | Concentrated urine from dehydration |
| Foul or fishy | Urinary tract infection; bacterial vaginosis in women |
| Sweet or fruity | High blood sugar or ketones in diabetes, or fasting and very low-carbohydrate diets |
| Sulfur or cabbage-like | Asparagus, garlic, onions; some medicines and supplements |
| Musty | Phenylketonuria (rare, detected by newborn screening), liver disease |
| Maple syrup | Maple syrup urine disease (rare, in newborns) |
| Fecal | Fistula between bowel and bladder (rare), often with bubbles of gas in urine |
Sweet-smelling urine and diabetes
When blood sugar is high, sugar spills into the urine and can make it smell sweet. When the body burns fat for fuel because it lacks insulin, it makes ketones, giving a fruity or nail-polish-remover smell. With vomiting, abdominal pain, deep fast breathing or drowsiness, this can be diabetic ketoacidosis, an emergency.
Asparagus smell
Many people notice a strong, sulfur-like smell within 15 to 30 minutes of eating asparagus. It is harmless, and not everyone can smell it.
How doctors assess urine changes
A doctor will ask about the color or smell change, how long it has lasted, fluids, diet, medicines, vitamins, and symptoms such as burning, fever, pain, swelling, thirst or weight loss. Tests usually include:
- Urine dipstick: checks for blood, protein, glucose, ketones, white cells and nitrites
- Urine microscopy and culture: confirms infection and identifies bacteria
- Blood tests: kidney and liver function, blood sugar, HbA1c
- Imaging: kidney ultrasound or CT for stones, blood in the urine or recurrent infection
Treatment
- Dehydration: drink enough to keep urine pale yellow.
- Foods, vitamins and medicines: no treatment needed. Do not stop prescribed medicines without advice.
- Urinary tract infections: antibiotics after a urine test. Seek care quickly if you have fever or back pain.
- Diabetes: blood sugar control; emergency treatment for ketoacidosis.
- Kidney disease: blood pressure control, medicines that reduce protein loss, and specialist care.
- Stones: fluids, pain relief, and procedures for larger stones.
Frequently asked questions
What does cloudy urine mean?
Cloudy urine is most often caused by a urinary tract infection, dehydration or harmless crystals. If it comes with burning, frequent urination, fever or a strong smell, a urine infection is likely and you should see a doctor.
Why does my urine smell strong?
Strong-smelling urine is usually due to dehydration, certain foods such as asparagus or garlic, or vitamins. A foul smell with burning or cloudy urine suggests infection, and a sweet or fruity smell can be a sign of high blood sugar.
Is foamy urine a sign of kidney problems?
Occasional foam is normal, especially if you urinate forcefully. Persistent foam every time can mean protein in the urine, a sign of kidney damage from diabetes, high blood pressure or kidney disease. A simple urine test can check.
What does sweet-smelling urine mean?
Sweet or fruity-smelling urine can mean high blood sugar or ketones, as in uncontrolled diabetes. It can also happen with fasting or very low-carbohydrate diets. If you also feel thirsty, are passing a lot of urine, or feel unwell, get your blood sugar checked.
Why is my urine green or blue?
Green or blue urine usually comes from food dyes or medicines such as amitriptyline, propofol or methylene blue. It is rarely caused by infection with certain bacteria. It is usually harmless but mention it to your doctor if it persists.
Sources
This guide was written from current patient and clinical guidance, including:
- MedlinePlus: Urine - abnormal color; Urine odor
- Mayo Clinic: Urine color
- National Kidney Foundation: What your urine color says about you; Foamy urine
- NIDDK: Bladder infection (urinary tract infection) in adults
- NHS: Urinary tract infections