Causes of dark red urine

Red or brown urine may contain blood from the urinary tract, although foods, medicines, menstrual blood, or muscle pigment can change its appearance. Dark, strong-smelling urine after heavy sweating or not drinking enough may occur with dehydration. Heat exhaustion can add weakness, headache, dizziness, nausea, or heavy sweating.

Pain or burning with urination, frequent urges, side pain, fever, or clots gives a clinician more useful information. Liver inflammation such as hepatitis A or hepatitis B can make urine dark, often alongside yellow eyes or skin, pale stools, nausea, or unusual tiredness. Colour alone cannot identify the cause.

Check whether the colour remains after drinking fluids normally and resting in a cool place, unless a clinician has limited your fluids. Do not ignore red or cola-coloured urine that continues. Arrange medical advice for a urine test and review of medicines, recent exercise, pain, fever, menstrual timing, and possible liver symptoms. Do not stop prescribed treatment without advice.

Seek urgent care for dark red urine with severe side or abdominal pain, inability to pass urine, clots, faintness, confusion, high fever, yellow skin with vomiting, or marked weakness after heat exposure. Prompt review is needed for visible blood, repeated episodes, or urine that stays dark despite normal fluid intake.

Ask whether the colour is likely to be blood or another pigment, which urine and blood tests are needed, whether heat or dehydration contributed, and which warning signs require emergency attention.