Dark urine even when drinking water: what to know

Water intake is only one part of urine colour. Sweat, diarrhoea or vomiting can offset what you drink, while vitamins, medicines and foods may add colour. Red or brown urine can contain blood or pigments released from muscle; dark urine with yellow eyes or skin may relate to bile flow or the liver. Burning and frequent urination can occur with infection. These causes have different treatments, so a darker shade should be considered alongside symptoms and urine output.

Continue ordinary fluid intake unless a clinician has advised a restriction. Do not stop prescribed medicines without checking first, but make a list of every medicine, supplement and recent food. Note the shade in daylight, when it appears, whether it clears later, and any pain, fever, swelling or change in output. If the finding continues, arrange an appointment; a clinician can decide whether urine or blood tests are useful.

Seek urgent help for very little urine, fainting, confusion, severe weakness, severe muscle pain or inability to keep fluids down. Contact a clinician promptly for brown or tea-coloured urine, visible blood, jaundice, fever with side pain, or painful urination. Do not wait for extra water to correct these warning signs.

Ask which causes fit your colour and symptoms, whether your medicines or supplements are relevant, and whether testing should check for infection, blood, kidney changes, liver-related pigment or muscle pigment. Tell the clinician about recent illness, exercise, fluid losses and urine frequency.