Dark yellow urine causes

The kidneys conserve water when you sweat, exercise, or have vomiting or diarrhoea, making urine more concentrated; this is the usual mechanism behind a deeper yellow shade and is discussed in [Dehydration](/conditions/dehydration/). B vitamins and some medicines can change pigment. Burning, urgency, frequency, blood, or side pain suggests a urinary issue rather than colour alone. Dark brown urine with jaundice, pale stools, or nausea may occur with liver inflammation, including [Hepatitis A](/conditions/hepatitis-a/) or [Hepatitis B](/conditions/hepatitis-b/).

Think about recent heat, activity, illness, diet, new medicines, and supplements. Drink fluids regularly, but do not use forced hydration as a test or stop prescribed treatment on your own. If the shade does not settle, or if other symptoms are present, book a primary-care review. The clinician may ask for a urine sample and blood tests based on your history.

Seek prompt help for confusion, fainting, severe weakness, repeated vomiting, very little urine, yellow eyes or skin, visible blood, severe abdominal or back pain, or cola-coloured urine. Heat exposure with headache, dizziness, nausea, or worsening weakness needs quick attention because [Heat Exhaustion](/conditions/heat-exhaustion/) can worsen without cooling and fluids.

Ask: Which causes fit my other symptoms? Could my medicines or vitamins be responsible? Do I need urine testing, kidney testing, or liver tests?