What should you know about occasional dark urine?

Occasional dark urine may be caused by concentrated urine, but persistent discoloration or other symptoms should be assessed. The shade can also change after some foods, supplements, or medicines, so colour alone cannot identify the cause.

Dark yellow urine often occurs when urine is concentrated, including during dehydration or after sweating in hot conditions. Heat exhaustion can cause dark urine together with heavy sweating, weakness, headache, nausea, or dizziness. Tea-coloured or brown urine, especially with yellowing of the eyes or skin, pale stools, nausea, or upper abdominal discomfort, can occur with liver inflammation such as hepatitis A or hepatitis B. These conditions cannot be diagnosed from colour alone.

Think about the timing: note recent heat exposure, exercise, fluid intake, foods, vitamins, and new medicines. Drink fluids normally if you have not been told to restrict them, and check whether the colour returns to your usual shade. Arrange medical advice if dark urine continues, returns without an obvious trigger, or appears with pain, fever, jaundice, or unusual tiredness.

Seek urgent help for confusion, fainting, severe weakness, inability to keep fluids down, very little urine, severe abdominal pain, or yellow skin with worsening illness. After significant heat exposure, move to a cool place and seek prompt care if symptoms do not settle quickly or you feel increasingly unwell.

Ask whether urine and blood tests are needed, whether a medicine or supplement may be responsible, and which warning signs require immediate review. Describe the colour, when it started, recent heat or exercise, fluid intake, and any jaundice, pain, fever, or change in bowel movements.