Dark urine: causes, warning signs and care

Dark urine can occur when urine is concentrated or when pigments, blood, medicines, or illness change its colour.

It may look deep yellow, amber, orange, tea-coloured, brown, red, or cola-coloured. Compare it with your usual urine, and notice whether the change follows sweating, vomiting, diarrhoea, exercise, a new medicine, a supplement, or certain foods. Cloudiness, foam, a strong smell, pain, or reduced urine output are useful details to record.

Seek urgent medical assessment if dark urine occurs with inability to pass urine, severe abdominal or back pain, fainting, confusion, yellow skin or eyes, or visible blood. Get prompt help if fluid loss is accompanied by severe weakness, persistent vomiting, or worsening dizziness. Dark urine after a significant injury or with severe muscle pain also needs urgent review.

The causes below are alphabetical and do not indicate how likely any one cause is. Dehydration makes urine more concentrated. Heat exhaustion can cause fluid and salt loss through sweating. G6PD deficiency can lead to breakdown of red blood cells after particular triggers, which may darken urine. Hepatitis A and hepatitis B can affect the liver and may be associated with darker urine and yellowing of the skin or eyes.

Dark urine can be a presentation of these conditions, but colour by itself cannot establish the cause.

Assessment starts with questions about fluids, heat exposure, food, medicines, supplements, recent illness, pain, and family or personal history. A urine sample can check for blood, protein, infection markers, or other changes. Blood tests may assess hydration, liver function, kidney function, or red blood cell breakdown. Imaging may be considered when symptoms suggest a blockage or another structural cause.

If fluid loss is the issue, a clinician may advise oral fluids or medically supervised rehydration, depending on how unwell you are. Heat exhaustion requires cooling, rest, and fluid replacement. Management for liver inflammation, red blood cell breakdown, or urinary tract problems is directed by the diagnosis. Do not stop prescribed medicine solely because of urine colour without medical advice, unless you are having an emergency reaction.

Drink regularly during hot weather, physical activity, vomiting, or diarrhoea, adjusting for any fluid limit a clinician has given you. Take breaks from heat and wear suitable clothing. If you have G6PD deficiency, follow your personalised advice about substances and medicines to avoid. Keep a list of medicines and supplements so a clinician can quickly check whether they may affect urine colour.

Mention thirst, dry mouth, dizziness, reduced urination, fever, nausea, itching, pale stools, yellowing of the skin or eyes, burning when urinating, abdominal pain, back pain, or muscle pain. The combination and timing of symptoms are more informative than urine colour alone.

A brief colour change after reduced fluid intake may settle as hydration improves, but persistent, recurrent, or unexplained dark urine should be assessed. Untreated fluid loss can worsen weakness and dizziness. When a liver, blood, or urinary condition is involved, early assessment helps guide the right treatment and monitoring.