Dark yellow urine and kidney stones: what to know

When you drink less fluid, urine becomes more concentrated and can look deep yellow. Heat, sweating, vomiting, or diarrhoea can make this more noticeable. Kidney stones are solid deposits that can irritate or obstruct the urinary tract. A stone may cause severe pain in the side or back that comes in waves, pain moving towards the groin, nausea, or blood-tinged urine. Dark yellow colour alone does not show that a stone is present.

A stone can also make urination painful or difficult if it moves near the bladder or blocks urine flow. These symptoms deserve attention even when the urine colour changes only slightly.

Sip fluids regularly if you can drink normally, and notice whether the urine becomes lighter. Do not force large amounts of fluid if you are vomiting or have been told to restrict fluids. Record when pain began, where it travels, whether you see blood, and whether you can pass urine. A GP consultation can assess your symptoms and decide whether urine testing or imaging is appropriate. An abdominal ultrasound may help look for a blockage or a stone, although the clinician chooses the test based on your examination.

Seek urgent medical help for severe or persistent flank or abdominal pain, fever or chills with urinary symptoms, repeated vomiting, visible blood in urine, or difficulty passing urine. A blocked urinary tract with infection can become serious. Seek prompt advice if you feel faint, confused, unusually weak, or unable to keep fluids down.

Ask whether your symptoms fit a stone, dehydration, or another urinary problem; whether you need a urine test or abdominal ultrasound; how to manage pain safely; and which changes mean you should return urgently.