If you’ve ever had a runny nose or sneezed without a tissue, you’ve probably become close and personal with your snot. You may have noticed that it changes color or texture from time to time. Nasal discharge can be clear, green, black, and many other colors in between.

Your mucus is there to protect your nose and sinuses from things like dust, bacteria, and other environmental dangers. Why might mucus change color? It usually has something to do with what’s going on inside or outside your body. You may be healthy or have a cold, allergies, or another underlying condition.

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.

clearwhitegreen or yellowred or pinkbrown or orangeblack
“normal” or healthy
allergic sinusitis
common cold
fungal infection
injury or irritation
nonallergic or pregnancy rhinitis
sinusitis
smoking/drug use

Clear snot is considered “normal” or healthy. Your body produces around 1.5 quarts of this discharge each day, though you likely swallow most of it. This type of mucus is made up of water with proteins, antibodies, and salts. Once it reaches the stomach, it dissolves. Your body continues making it around the clock to help line and protect your nose and sinuses.

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.

Other symptoms may include:

  • postnasal drip
  • itchy, watery eyes
  • sneezing
  • coughing
  • itchy nose, throat, or roof of mouth
  • discolored skin under the eyes
  • fatigue

Some women develop a runny nose during pregnancy called nonallergic rhinitis. Researchers explain that this condition is caused by hormonal changes and can develop at any gestation. It’s more common between weeks 13 and 21. This condition usually resolves within a couple weeks of delivery.

If you’re feeling congested or stuffy, you may notice your snot is white. You may also experience swelling or inflammation in your nose and a slow flow of nasal mucus. Being stuffy makes your snot lose its water content. It becomes thick and even cloudy, both signs that you may have a cold or infection brewing.

The common cold can make you feel generally unwell. Your symptoms will usually develop between one and three days after being exposed to the virus. Children are particularly prone to colds. Adults, on the other hand, may experience between two and three colds each year.

Other symptoms include:

  • sore throat
  • congestion
  • cough
  • sneezing
  • low-grade fever, or a fever above 98.6°F (37°C) but lower than 100.4°F (38°C)
  • mild body aches
  • mild headache

Yellow mucus is a sign that whatever virus or infection you have is taking hold. The good news? Your body is fighting back. 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 and tinge it a yellowish-brown.

Your illness may last anywhere from 10 to 14 days, but keep an eye on your nasal discharge.

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.

Still, if you’ve had your cold or infection for 12 days or more, it may be a good time to make an appointment. You may have a bacterial sinus infection or another bacterial infection that requires medication. Look for other signs you’re not getting better, like fever, headache, or nausea.

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

To prevent nosebleeds, consider:

  • applying Vaseline or another ointment to the nasal passages three times a day
  • using saline nose spray 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

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

If your child is experiencing bleeding, call their pediatrician. This is especially important if your tot is under age 2.

If your blood is the result of an acute injury like a car accident, seek medical attention to rule out more serious issues.

You should also see your doctor if you:

  • have difficulty breathing
  • bleed for more than 30 minutes
  • produce more than about 1 tablespoon of blood

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.

Black nasal mucus may be a sign of a serious fungal infection. While not common, people with compromised immune systems may be susceptible to this type of 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 in areas like Sudan and India. 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.

People who smoke or use illicit drugs may also have black snot.

Whatever the potential cause, it’s a good idea to check in with your doctor for a more formal diagnosis.

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 snot that is hard. In some cases, drinking more water may help thin your mucus. 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 tear in the membranes surrounding your brain, likely from injury or certain medical conditions, like hydrocephalus.

Other symptoms of a CSF leak include:

  • nausea
  • vomiting
  • neck stiffness
  • sensitivity to light or sound
  • positional headaches; for example, you may feel more pain while sitting up versus lying down

If you suspect you may have a CSF leak, seek medical attention.

It may be difficult to tell the difference between a cold or other viral infection, and a bacterial infection. 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 7 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

In rare cases, the infection may spread to the eye or brain. Seek medical attention immediately if you notice any of the following symptoms:

  • all-day swelling or redness around the eyes
  • severe headache
  • sensitivity to light
  • pain in the back of your neck
  • increasing irritability
  • persistent vomiting

Think your snot may be the result of allergies? There are several things you can do to clear your congestion:

  • Try avoiding irritants, like ragweed, grasses, and trees on high-pollen days. If you can’t completely avoid the outdoors, avoid being outside between 5 and 10 a.m.
  • Keep your windows closed and use air-conditioning.
  • Don’t hang your laundry outside to dry. Mold and pollen can cling to your clothing, towels, and sheets.
  • Take precautions while doing yard work. A dust mask can protect you from irritants while you’re mowing, raking, or gardening.
  • Speak with your doctor about allergy medicines. You may take either prescription or over-the-counter (OTC) antihistamines or decongestants.

For congestion from colds and other conditions:

  • Gently blow your nose as often as needed. Sniffing and swallowing the nasal mucus is another option in the short term.
  • Drink lots of water — at least eight 8-ounce glasses a day — to help thin your mucus for easier blowing.
  • Use a humidifier to add moisture to the air you breathe.
  • Spray a saline solution in your nasal passages. This is a saltwater solution that doesn’t contain medication, so you may use it two or three times each day.
  • If your congestion is severe, consider using a decongestant, like Afrin, for up to three days.
  • Use a bulb-syringe to remove excess snot in babies and small children.

Alternatively, you may try using a neti pot to rinse debris or mucus from your nose. You can find pots at most pharmacies.

To use a neti pot:

  1. Mix together a saltwater solution using distilled or sterilized water.
  2. Tilt your head to one side over a sink. Place the spout in your upper nostril.
  3. Breathe in through your mouth and pour the solution into the upper nostril. It will drain through your lower nostril.
  4. Repeat this process on the other side.
  5. After use, rinse your pot with distilled or sterilized water and let air dry.

Snot is produced by your sinuses 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. If you notice warning signs of bacterial infection or have other concerns about your health, see your doctor.