What should you know about urine that suddenly looks dark?

Deep yellow urine commonly follows reduced fluid intake, sweating, vomiting, or diarrhoea. Foods, supplements, and medicines can also change colour. Tea-coloured or brown urine may contain blood, muscle pigment, or bile pigments. Liver inflammation such as [Hepatitis A](/conditions/hepatitis-a/) or [Hepatitis B](/conditions/hepatitis-b/) can occur with yellow eyes or skin, pale stools, nausea, poor appetite, or upper abdominal discomfort. Dark urine is a symptom, not a diagnosis, and colour alone cannot identify its cause.

Consider recent fluid loss, heat exposure, exercise, foods, and new medicines. Drink water steadily if you can and have no fluid restriction, then observe whether the colour lightens. Do not discontinue prescribed medicine without advice. If it stays dark, returns, or has no clear explanation, arrange a clinical assessment and urine testing. See [Dark Urine](/symptoms/dark-urine/) for related guidance.

Seek urgent care for dark urine with yellow skin or eyes, severe abdominal pain, confusion, fainting, very little urine, repeated vomiting, or marked weakness. After heat exposure, headache, dizziness, cramps, heavy sweating, or worsening illness can indicate [Heat Exhaustion](/conditions/heat-exhaustion/). Get prompt advice for visible blood, fever, or back pain. [Dehydration](/conditions/dehydration/) can require treatment when fluid loss is substantial.

Tell your clinician when the colour changed, what it looked like, recent fluid loss or heat exposure, exercise, medicines, pain, fever, bowel changes, and any yellowing. Ask whether you need urine, kidney, liver, or blood tests.