This is a self-check tool, not a diagnosis. If you see visible blood, pass a stone, have severe pain, fever, vomiting, or haven't urinated in 12+ hours, seek medical care now - call 911 (US) or 999 (UK). For persistent colour changes lasting more than 24-48 hours, contact your clinician. This site is not affiliated with Cleveland Clinic, Mayo Clinic, or any medical institution.

Medications and Foods That Change Urine Colour (Searchable Lookup)

Updated April 2026 - 25+ entries with onset times and clinical notes

Why this matters: One of the most common reasons for unexpected urine colour is a medication or food taken in the last 24-48 hours. This lookup lets you enter the substance and see what colour to expect, how quickly it appears, and when it clears. Most medication-related colour changes are harmless and expected.

25 results

Name	Type	Colour	Onset	Concern?
Rifampin / rifampicin	medication	Orange-red	1-4 hours	Usually no
Phenazopyridine (Pyridium, AZO)	medication	Bright orange	1-2 hours	Usually no
Metronidazole (Flagyl)	medication	Dark brown	During course	Usually no
Nitrofurantoin	medication	Brown-yellow	During course	Usually no
Amitriptyline	medication	Blue-green	Days to weeks	Usually no
Methylene blue	medication	Blue-green	1-4 hours	Usually no
Propofol	medication	Green	During/after infusion	Usually no
Indomethacin	medication	Blue-green	During use	Usually no
Riboflavin (B2)	medication	Bright yellow	2-4 hours	Usually no
Levodopa (L-DOPA)	medication	Dark brown	During use	Usually no
Chloroquine / hydroxychloroquine	medication	Brown	During use	Usually no
Methyldopa	medication	Dark brown	During use	Usually no
Senna laxative	medication	Amber-brown	6-12 hours	Usually no
Cascara	medication	Brown	6-12 hours	Usually no
Sulfasalazine	medication	Orange	During use	Usually no
Vitamin C (ascorbic acid) megadose	medication	Orange tint	2-6 hours	Usually no
Isoniazid (INH)	medication	Orange-brown	During course	Usually no
Beetroot	food	Pink-red	2-8 hours	Usually no
Blackberries / bilberries	food	Pink-red	2-6 hours	Usually no
Rhubarb	food	Brown	2-6 hours	Usually no
Fava beans (broad beans)	food	Dark brown	2-8 hours	Possible
Carrots / beta-carotene	food	Orange tint	Hours to days	Usually no
Asparagus	food	Greenish tint (+ odour)	15-30 minutes	Usually no
Blue food dye (FD&C Blue No. 1)	food	Blue-green	1-4 hours	Usually no
B12 (high dose)	medication	Red-pink (rare)	Hours	Usually no

Fava beans (broad beans) - Note: CONCERN if you have G6PD deficiency - seek care. Otherwise benign in most people.

Rifampin / rifampicin: Expected, documented side effect. Also colours sweat, tears, and saliva.

Phenazopyridine (Pyridium, AZO): UTI pain relief. Can interfere with dipstick urine tests.

Metronidazole (Flagyl): Common antibiotic. Expected darkening.

Common Questions

Why does rifampin turn urine orange?

Rifampin (rifampicin) is a reddish-orange pigment itself - it is derived from a bacterial compound called rifamycin, which naturally has a bright orange-red colour. When your body processes rifampin, it excretes the compound and its metabolites through urine, bile, and sweat. This produces orange-to-red urine within one to four hours of taking the medication. The effect persists throughout treatment and clears after the course ends. Rifampin also colours tears, sweat, and saliva orange - patients who wear soft contact lenses should switch to glasses during treatment as rifampin can permanently stain lenses.

Why do B vitamins turn urine bright yellow?

Riboflavin (vitamin B2) is a naturally fluorescent compound. Your body cannot store excess riboflavin - it is water soluble - so any intake above your immediate cellular needs is rapidly excreted through the kidneys. Even relatively small supplemental doses (5-10mg, which is the typical B-complex content) produce visibly brighter, more saturated yellow urine. The effect appears within two to four hours of taking the supplement and clears within four to eight hours. Taking vitamins with food and drinking plenty of water slightly dilutes the colour, but does not eliminate it.

Is any food-related colour change dangerous?

One specific scenario is dangerous: fava beans (broad beans) in people with G6PD deficiency. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic condition affecting red blood cells, more common in people of African, Mediterranean, and Middle Eastern descent. In these individuals, fava beans trigger haemolysis (breakdown of red blood cells), which can produce dark brown or even black urine from haemoglobin. If you have G6PD deficiency and develop dark urine after eating fava beans, this is a medical emergency - seek care promptly.

In people without G6PD deficiency, fava beans may produce mildly dark urine without haemolysis, which is harmless.

When to Be Concerned About Medication-Related Colour

Most medication-related urine colour changes are documented, expected, and harmless. However, pay attention to these situations:

!The colour change is not listed as a known side effect of your medication - it may be a sign of drug-induced liver or kidney injury
!You see the expected colour change plus other symptoms (yellow eyes, fatigue, nausea, swelling)
!The colour is dramatically more intense than you expected, or does not clear after stopping the medication
!You have G6PD deficiency and develop dark urine after fava beans, certain antimalarials, or infections

When in doubt, consult your pharmacist - they have access to comprehensive drug side effect profiles and can quickly confirm whether a colour change is expected or warrants GP review.

Colour selector Orange urine Bright yellow Green/blue

Sources: Mayo Clinic; DailyMed (NIH) drug information database; MedlinePlus drug information.