What should you know about dark thick urine?

Urine can look darker and thicker when the body has less fluid available. Sweating, vomiting, diarrhoea, fever, or spending time in heat can contribute to dehydration. Heat exhaustion may also cause dark urine alongside weakness, dizziness, headache, nausea, or heavy sweating. Brown or tea-coloured urine, yellowing of the eyes, pale stools, or itching can point to a liver problem such as hepatitis A or hepatitis B. A red, pink, smoky, or cola-like colour may reflect blood or pigment rather than simple concentration.

If you feel well and have been drinking little, take regular sips of water and note whether the urine becomes lighter. Replace fluids gradually after sweating or stomach illness; oral rehydration fluid may be useful when losses have been substantial. Do not force large amounts if you have been told to restrict fluids. Check whether food, supplements, or a new medicine could alter colour, and keep a note of when the change began. A clinician can assess a urine sample and review hydration, liver, and kidney-related symptoms.

Seek urgent help for confusion, fainting, severe weakness, inability to keep fluids down, very little urine, severe abdominal or back pain, or trouble breathing. Arrange prompt medical review for brown urine, visible blood, yellow skin or eyes, fever, burning urination, swelling, or colour that does not improve with normal hydration.

Ask whether your urine needs testing, whether medicines or supplements could explain the colour, and which symptoms would suggest dehydration, a urinary problem, or liver inflammation.