My urine colour is dark yellow

Dark-yellow urine is often concentrated because of low fluid intake, sweating, or fluid loss, but context matters. The colour may become lighter after you drink enough fluids. A persistent change, very dark or brown urine, or symptoms such as pain, fever, yellow skin, or reduced urination should be assessed.

Dehydration can make urine more concentrated, especially after exercise, vomiting, diarrhoea, fever, or time in hot weather. Heat exhaustion may occur with heavy sweating, dizziness, headache, weakness, nausea, or muscle cramps. Some foods, supplements, and medicines can alter urine colour. Liver inflammation, including hepatitis A or hepatitis B, may cause dark urine with yellowing of the eyes or skin, pale stools, nausea, or discomfort under the ribs. Dark urine can have other explanations, so colour alone cannot identify its cause.

Drink fluids regularly and monitor whether the urine becomes lighter over the following hours. Replace fluid gradually after sweating or illness; oral rehydration advice from a pharmacist may help when vomiting or diarrhoea is involved. Avoid alcohol while you are unwell. Note medicines, supplements, recent heat exposure, and any change in urine amount, smell, or pain. Do not force large amounts of fluid if a clinician has told you to restrict fluids.

Seek urgent help for confusion, fainting, severe weakness, inability to keep fluids down, very little urine, or signs of severe heat illness. Arrange prompt medical care for brown or tea-coloured urine, yellow skin or eyes, fever, flank pain, painful urination, blood, or ongoing vomiting. Book an appointment if the colour stays dark despite usual drinking or keeps returning.

Ask whether you need a urine test or blood tests, and whether medicines, dehydration, infection, or liver problems could explain the change. Mention fluid intake, heat exposure, recent illness, travel, new products, and all medicines or supplements.