Brown urine can be a sign of severe dehydration, certain drugs, liver or kidney problems, or intense exercise. Blue or green urine is rare and usually linked to medications, dyes, or uncommon medical conditions.
You should see a doctor if urine color changes come with pain, burning, fever, back pain, blood, or if abnormal color persists even when you are well hydrated. In most cases, though, changes are harmless and related to lifestyle factors.
