What should you know about urine that is too dark?

Deep yellow urine often occurs when it is concentrated, such as after sweating, vomiting, diarrhoea or not drinking enough. Darker shades can also follow certain foods, supplements or medicines. Brown, tea-coloured or cola-coloured urine may reflect bile pigments, blood or muscle pigment and should not be explained away by hydration alone.

Dehydration and heat exhaustion can develop after fluid and salt loss, especially in hot conditions. Dark urine with yellow eyes, pale stools, itching or abdominal discomfort can accompany a liver or bile problem. Colour by itself cannot distinguish among these causes.

Consider recent heat, exercise, illness, foods and medicines, and note whether the colour changes after normal drinking. Replace fluids gradually if you have been sweating or losing fluid, unless you have a medical fluid restriction. Arrange a clinical review when the colour persists, returns without an obvious reason or appears brown, red or cola-coloured.

Seek urgent help for dark urine with confusion, faintness, severe weakness, very little urine, inability to keep fluids down or signs of heat exhaustion. Prompt medical advice is also needed with yellow skin or eyes, pale stools, fever, significant abdominal or side pain, or visible blood.

Ask whether the shade suggests concentration, bile, blood or another pigment, whether urine and blood tests are needed, and how your medicines or recent heat exposure affect the interpretation.