What should you know about dark first-morning urine?

Urine commonly looks deeper yellow after several hours without drinking. Dehydration can make this more noticeable, especially after heat, exercise, vomiting or diarrhoea. Food, supplements and medicines can also change colour. Brown urine, tea-coloured urine, red urine, cloudy urine, or a strong change that continues through the day can have other causes, including liver or urinary conditions. Dark urine alone does not identify one diagnosis.

Drink fluids regularly unless a clinician has told you to restrict them, then observe whether the colour becomes lighter later in the day. Note any new medicines, supplements, pain, burning, fever, nausea or changes in bowel movements. Do not stop prescribed treatment without advice. If dark urine keeps returning, arrange a medical review; a clinician may ask for a urine sample and check other symptoms.

Seek urgent care for dark urine with severe weakness, confusion, fainting, inability to keep fluids down, or signs of heat exhaustion. Prompt assessment is also needed for yellow skin or eyes, pale stools, significant abdominal pain, fever, or blood-like urine. A sudden reduction in urination is another reason to seek same-day advice.

Ask whether your fluid intake, medicines or recent illness could explain the colour, and whether urine or blood tests are appropriate. Mention travel, heat exposure and any yellowing of the skin or eyes.