Dark yellow urine despite drinking lots of water

Urine colour reflects the fluid balance at the moment your kidneys make it, not only the amount you drank earlier. Sweat, hot weather, exercise, vomiting, or diarrhoea can offset intake; [Heat Exhaustion](/conditions/heat-exhaustion/) is a concern when heat symptoms accompany fluid loss. Vitamins, especially products containing B vitamins, and some medicines may deepen yellow colour. Dark brown urine, yellow eyes or skin, pale stools, nausea, or right-sided upper abdominal discomfort can point toward liver inflammation, including [Hepatitis A](/conditions/hepatitis-a/) or [Hepatitis B](/conditions/hepatitis-b/).

Check the colour at different times rather than after one drink, and keep a brief log of fluids, activity, bowel illness, supplements, and medicines. Drink to thirst unless you have been given a fluid limit; excessive water can itself be harmful. If urine remains dark over several days, or the volume is unusually small, contact a clinician. Bring a list or photo of every medicine and supplement to the appointment.

Get prompt care for very little urine, inability to keep fluids down, fainting, confusion, severe weakness, yellowing of the eyes or skin, blood, severe pain, or a tea- or cola-coloured appearance. Symptoms of dehydration such as intense thirst, dry mouth, dizziness, and worsening fatigue also merit attention; learn more about [Dehydration](/conditions/dehydration/).

Ask: Could a supplement or medicine be changing the colour? Is my fluid intake appropriate for my health? Would urine, kidney, or liver tests help explain the persistence?