Brown discharge from your body is almost always old blood. When blood leaves the body quickly, it looks red, but when it sits for a while or moves slowly, it oxidizes and turns brown, much like a cut apple darkens when exposed to air. The iron in your blood literally changes its chemical form, shifting from a state that carries oxygen (and appears bright red) to one that doesn’t (and appears dark brown). Where the brown stuff is coming from, how much there is, and what other symptoms accompany it determine whether it’s completely normal or worth investigating.
Brown Vaginal Discharge
This is the most common reason people search this question, and the most common explanation is simple: old blood leaving your body at the beginning or end of your period. Your menstrual flow is naturally slower during those phases, giving the blood more time to oxidize before it exits. The result is brown or dark brown spotting rather than the bright red flow you see mid-period.
Beyond your period, several other causes are worth knowing about:
- Ovulation spotting. About 3% of people experience light spotting mid-cycle when an egg is released. A temporary dip in estrogen triggers a small amount of bleeding that can appear brown, pink, or mixed with clear discharge.
- Hormonal contraception. Birth control pills and IUDs commonly cause breakthrough bleeding in the first few months of use, especially formulations low in estrogen. If this blood takes time to leave the body, it shows up brown.
- Implantation bleeding. When a fertilized egg embeds itself in the uterine lining, roughly one to two weeks after fertilization, it can cause light bleeding in various shades including brown. About 25% of pregnancies involve some implantation bleeding.
- Hormonal imbalances. Conditions like polycystic ovary syndrome (PCOS) can cause long gaps between periods, sometimes more than 35 days. That extended time allows old blood to accumulate and exit as brown discharge.
- Bacterial vaginosis (BV). If your brown discharge comes with a fishy odor, especially around your period or after sex, a bacterial imbalance may be involved. BV is treatable with a prescription pill or cream.
If you’re in or approaching menopause and notice brown discharge, it’s worth having a doctor confirm whether the blood is coming from the vagina or the uterus. Uterine bleeding after menopause can signal other issues that need evaluation.
Brown Discharge During Pregnancy
Up to 25% of pregnant people experience some bleeding or spotting, and brownish spotting is by far the most common type. In one large study, nearly 90% of patients who reported pregnancy-related bleeding described it as brownish spotting. Much of the time, it’s harmless, especially in very early pregnancy when implantation bleeding is the likely cause.
That said, first-trimester bleeding does carry an increased risk of complications including miscarriage and premature delivery, particularly when it stems from a subchorionic hematoma (a pocket of blood between the uterine wall and the pregnancy sac) or an ectopic pregnancy. A single episode of light brown spotting in early pregnancy is common and often resolves on its own, but repeated bleeding, heavy flow, or bleeding accompanied by cramping or dizziness warrants prompt evaluation.
Brown Nasal Mucus
If the brown stuff is coming from your nose, two things are most likely. First, dried blood from minor nosebleeds or nasal irritation. The small blood vessels inside your nose are fragile and burst easily when the air is dry, when you blow your nose too hard, or when allergies inflame the tissue. That old blood mixes with mucus and comes out brown.
Second, environmental exposure. Smoking, dust, and air pollution can all turn your mucus brown. If you’ve been around smoke, construction dust, or heavy traffic, brown mucus is your nose doing its filtering job. Persistent brown or black nasal mucus without an obvious environmental cause can occasionally point to a more serious infection, including fungal sinusitis, and is worth getting checked.
Brown Rectal Discharge
Brown or blood-tinged mucus from the rectum has a different set of causes. Internal hemorrhoids are the most common and least concerning. But inflammation of the rectum, called proctitis, can also produce mucus mixed with blood or pus. Proctitis has several triggers: inflammatory bowel diseases like ulcerative colitis and Crohn’s disease, sexually transmitted infections (gonorrhea, chlamydia, herpes, syphilis), certain bacterial infections like C. diff, and even side effects of radiation therapy.
Passing blood, mucus, or pus from the rectum along with severe abdominal pain is a reason to see a doctor promptly. Occasional streaks of blood on toilet paper after straining are far less concerning, though persistent changes in bowel habits or discharge still deserve attention.
Brown Fluid From a Wound
Healing wounds go through stages, and the fluids they produce change along the way. Clear or slightly yellowish fluid is normal serous drainage, your body’s way of cleaning the wound. A light pink fluid means a small amount of blood is mixed in, which is also normal during healing.
Brown fluid from a wound is a different story. Thick white, yellow, or brown drainage is classified as purulent, meaning bacteria have likely entered the wound and caused an infection. Infected wound drainage often has an unpleasant smell. If you notice brown or discolored pus from a wound, especially alongside spreading redness, increasing pain, swelling, or fever, the wound needs medical treatment.
Brown Ear Drainage
Your ears naturally produce wax that ranges from light yellow to dark brown, and sometimes that wax works its way out on its own. This is completely normal. The color of earwax darkens with age and exposure to air, so dark brown wax alone isn’t a concern.
What’s different from normal wax is fluid drainage, which can signal a middle ear infection. Infections build pressure behind the eardrum, and if the eardrum ruptures, thick yellow or brown fluid may leak out, sometimes with significant pain beforehand. Ongoing drainage without pain can indicate a chronic ear condition. Fluid with a foul smell may point to an abnormal cell growth in the middle ear called a cholesteatoma, which needs medical treatment. Clear or blood-tinged fluid after a head injury is a medical emergency, as it could indicate fluid leaking from around the brain.
Brown Nipple Discharge
Brown or dark-colored discharge from the nipple is most commonly caused by mammary duct ectasia, a condition where the milk ducts beneath the nipple widen, typically with age. The duct walls thicken and fill with fluid, sometimes becoming blocked with a sticky substance. This can cause discharge that appears dirty white, yellowish, greenish, or dark brown to black, sometimes with swelling or tenderness around the nipple.
Mammary duct ectasia is benign and often resolves without treatment. However, any new nipple discharge, especially if it’s spontaneous (happening without squeezing), comes from only one breast, or is accompanied by a lump or skin changes, should be evaluated to rule out other causes.