What should you know about constant dark yellow urine?

Urine becomes darker when it contains less water, which can happen after sweating, vomiting, diarrhoea, fever, or simply drinking less. Dehydration is more likely when you also have thirst, a dry mouth, dizziness, headache, or reduced urination. Heat Exhaustion can cause fluid loss along with weakness, nausea, headache, and heavy sweating.

Dark urine that is brown or tea-coloured, especially with yellowing of the eyes or skin, pale stools, itching, abdominal discomfort, or unusual tiredness, can occur with liver inflammation such as Hepatitis A or Hepatitis B. Food, supplements, and some medicines can also change urine colour. Colour alone cannot identify the cause.

If you feel well and have been drinking little, take regular fluids and monitor whether the urine lightens. Replace fluid lost through sweating or illness, following personal advice if you have heart or kidney disease. Avoid excessive heat and alcohol while unwell. Note changes in colour, smell, amount, pain, fever, bowel symptoms, and any new medicine or supplement. Arrange a review if the colour remains dark despite normal drinking or keeps returning.

Seek urgent help for confusion, fainting, inability to keep fluids down, severe weakness, very little urine, or signs of serious heat illness. Get prompt medical advice for yellow skin or eyes, severe abdominal pain, fever with marked illness, painful urination, or blood in the urine. Persistent unexplained dark urine also deserves a clinical review.

Ask whether the colour fits dehydration, a medicine effect, or a liver or urinary problem, and whether urine or blood tests are appropriate.