Can dehydration cause dark urine?

Along with dehydration, concentrated urine may occur after sweating, vomiting, diarrhoea, fever, or simply drinking too little. Thirst, a dry mouth, headache, tiredness, dizziness, and passing urine less often can support dehydration as the explanation. Dark urine alone does not identify the cause.

Urine that stays dark after you have been drinking normally, or that looks red, brown, cloudy, or unusually foamy, may have another explanation. Medicines, foods, liver or kidney problems, and a urinary infection can change urine colour or appearance. Burning when you urinate, an urgent need to urinate, lower abdominal discomfort, or a strong smell should be assessed as possible urinary symptoms.

Sip water regularly and increase fluids gradually, especially after heat, exercise, vomiting, or diarrhoea. If fluid losses are substantial, an oral rehydration solution may help replace salts as well as water; follow the product directions. Rest somewhere cool if heat or sweating contributed, and avoid alcohol while you are dehydrated.

Notice whether your urine becomes lighter and you are passing it more normally as you rehydrate. People with heart, kidney, or liver disease, or those advised to restrict fluids, should check with a clinician before increasing their intake. Read more about [Dehydration](/conditions/dehydration/) and [Dark Urine](/symptoms/dark-urine/).

Seek urgent medical help if you are confused, faint, unusually drowsy, unable to keep fluids down, or passing very little or no urine. Get prompt assessment for dark urine with severe weakness, rapid breathing, severe abdominal or back pain, fever, or blood in the urine. Heat-related symptoms that worsen after moving to a cool place and drinking also need urgent attention; see [Heat Exhaustion](/conditions/heat-exhaustion/).

Arrange a medical review if the colour does not improve with normal fluid intake, keeps returning, or comes with pain or burning. Depending on your symptoms, a clinician may check a urine sample and look for causes such as [Urinary Tract Infection](/conditions/urinary-tract-infection/) or [Kidney Stones](/conditions/kidney-stones/).

Ask whether your urine colour and other symptoms fit dehydration, whether a urine test is needed, and how much fluid is appropriate for your health conditions. Tell the clinician about recent vomiting, diarrhoea, sweating, fever, new medicines, pain, burning, or changes in how often you urinate.