Injury, infection, and multiple health conditions can all change the color of your snot or nasal mucus. Knowing what these color changes mean can help to identify the cause.

You may have noticed that it changes color or texture occasionally. Nasal discharge can be clear, green, black, and many other colors.

Here’s your guide to the different conditions that can affect the color of your snot, tips to find relief, and when to see your doctor.

Your mucus protects your nose and sinuses from dust, bacteria, and other environmental dangers.

People with hay fever may have clear snot. A cold usually causes green or yellow snot. If your snot is another color, like red, brown, or black, it may be because of injury, smoking, or another issue.

clearwhitegreen or yellowred or pinkbrown or orangeblack
“normal” or healthy
allergic sinusitis
common cold
fungal infection
injury or irritation
nonallergic or pregnancy rhinitis
smoking/drug use
Infographic showing what the different colors of snot might meanShare on Pinterest
Design by Maya Chastain

Clear snot is considered “normal” or healthy. Rhinitis, or swelling of the mucosal membrane in the nose, is a common cause of increased snot production. This snot is often clear, and there are many types of rhinitis.

For example, allergic rhinitis or “hay fever” may also cause clear, runny nasal discharge. Although you may feel quite ill, allergies aren’t caused by a virus. The symptoms are your body’s response to irritants like pollen, cat or dog fur, and dust mites.

People may also experience rhinitis without allergen exposure. Doctors refer to this as nonallergic rhinitis.

If you’re feeling congested or stuffy, you may notice your snot is white. Congestion can cause snot to lose water content. It becomes thick and even cloudy — both signs that you may have a cold or infection brewing.

The common cold is a frequent cause of nasal congestion and white-colored snot. Your symptoms will usually develop between one and three days after exposure to the virus. Children are particularly prone to colds. Adults, on the other hand, may experience between two and three colds each year.

Yellow nasal mucus indicates that the body is fighting an infection.

The yellow color comes from the cells — white blood cells, for example — rushing to kill the offending germs. Once the cells have done their work, they’re discarded in your snot, giving it a dark yellowish tinge.

If your immune system kicks into high gear to fight infection, your snot may turn green and become especially thick. The color comes from dead white blood cells and other waste products.

But green snot isn’t always a reason to run to your doctor. In fact, some sinus infections may be viral, not bacterial. The presence of foreign bodies in the nasal passages may also cause yellow or green snot. In these instances, removing the offending item will resolve symptoms.

Blood in your snot will tinge it pink or red. Blood may flow a bit if you’ve blown your nose a lot or had a hit to the nose.

To prevent nosebleeds, consider:

  • applying Vaseline or another ointment to the nasal passages
  • using saline nose spray or gel to add moisture to your nasal tissues
  • trimming fingernails to deter nose-picking
  • adding moisture to the air with a humidifier
  • blowing your nose more gently

People who are pregnant may also experience bloody snot. This may be due to blood volume increases, hormones, or swollen nasal passages.

Brown snot may be the result of old blood exiting the body. Or you may have inhaled something red or brown that has discolored your mucus. Possibilities include dirt, snuff, or paprika.

Most commonly, people who smoke or are in households with smokers can have gray-black snot. Being subject to heavy air pollution may cause your snot to come out black. People who use illegal drugs may also have black snot.

Black nasal mucus may also be a sign of a fungal infection. While not common, people with compromised immune systems may be susceptible to this illness.

There are four types of fungal infections of the sinuses:

  • Mycetoma fungal sinusitis. This type results from clumps of spores invading the sinus cavities. Treatment involves scraping the infected sinuses.
  • Allergic fungal sinusitis. This type is more common in people with a history of allergic rhinitis. The infection must be surgically removed.
  • Chronic indolent sinusitis. This type is mostly found outside the United States. Other symptoms include headache, facial swelling, and visual disturbances.
  • Fulminant sinusitis. This type may cause damage to the sinuses and the bony area that contains the eyeballs and brain. Fulminant infections can cause necrosis, which can cause snot to appear black rather than the fungal spores causing discoloration.

However, the above fungal infections may cause black snot in every case.

The actual texture of your snot has a lot to do with its moisture content. Nasal mucus that flows freely has more water content than hard snot. Changes in texture can happen throughout the duration of an illness.

Watery discharge from the nose may be a warning sign of a cerebrospinal fluid (CSF) leak. A leak happens when there’s a membrane tear surrounding your brain, likely from injury or certain medical conditions, like hydrocephalus. If you suspect you may have a CSF leak, seek medical attention.

Color isn’t always the best indicator of whether you should see your doctor. Instead, pay attention to the duration of your illness and the worsening of your other symptoms.

Most colds last between 5 to 10 days. They usually peak in severity between days three and five. A bacterial infection may worsen as it progresses and continue beyond this time period.

Other signs you should make an appointment:

  • yellow snot accompanied by a fever that lasts three or four days in a row
  • headache that may be focused around or behind the eyes and is worse when bending over
  • swelling around your eyes or dark circles
  • all-day swelling or redness around the eyes
  • severe headache
  • sensitivity to light
  • pain in the back of your neck
  • increasing irritability
  • persistent vomiting

Your sinuses produce snot as protection against the outside world and its many viruses and other dangers. Most causes of congestion are due to viruses and allergies, not bacterial or fungal infections.

Unless you have an underlying medical condition, you may try at-home comfort measures to clear your congestion. See your doctor if you notice warning signs of a bacterial infection or have other concerns about your health.

Read this article in Spanish.