Dark Urine: Causes, When to Worry, and What to Do

Dark urine (amber, cola-colored, brown) usually signals concentrated urine or the presence of chromogens. While often benign, it can indicate serious pathology.

Common Benign Causes

• Dehydration: Concentrated urochrome pigment—most common cause; resolves with hydration.
• Foods: Beets, rhubarb, fava beans, aloe, food dyes.
• Medications: Rifampin (orange-red), metronidazole, nitrofurantoin, chloroquine, primaquine, methocarbamol, senna, cascara.
• Vitamins: High-dose B complex (bright yellow), riboflavin.

Medical Causes Requiring Evaluation

• Liver disease: Hepatitis, cirrhosis → bilirubinuria (dark yellow/brown, foam on shaking).
• Hemolysis: Hemolytic anemia, transfusion reaction → hemoglobinuria (red-brown, positive heme on dipstick, no RBCs on microscopy).
• Rhabdomyolysis: Myoglobinuria (tea-colored, positive heme, no RBCs); CK elevated.
• Glomerulonephritis: Hematuria (cola-colored, RBCs + casts on microscopy).
• Porphyria: Porphyrinuria (port-wine color, darkens on standing).
• Melanoma: Melaninuria (rare, very dark).

When to See a Doctor

• Dark urine persists despite good hydration (>2–3 L/day).
• Accompanied by: jaundice, abdominal/flank pain, fever, fatigue, edema, reduced urine output.
• Recent trauma, intense exercise, new medication.

Urinalysis, liver function tests, CK, and hemolysis workup guide diagnosis.