If you've ever looked into your tissue after you've had your nose blown and spotted yellow mucus, you may have wondered what your body wanted to tell you. No fear! Lime, the color of lemonade, is a sign that your body is doing what it should do when it comes to intruders.
Mucus is critical to the health of your respiratory and immune system.
This Slimy Fabric Helps Warming Moisten the Air That Breathe Anthony Del Signore, MD, Assistant Professor of Otolaryngology and Director of Rhinology and Endoscopic Skull Base Surgery at Mount Sinai Beth Israel, tells SELF. This is important because too cold and too dry breathing air can aggravate the respiratory system. Therefore it can burn in the winter to breathe outside . Although mucus is quite crude, it contributes quite well to the physical well-being.
Slime should also make you comfortable in other ways: as a watchful guard at the very front of your body's biological defense system. Michael Benninger MD, chair of the Cleveland Clinic's Head and Neck Institute, reports to SELF. Slime traps foreign invaders that could make you ill, including viruses, bacteria, and allergens. Ideally, small hair-like projections cilia blur these invaders so they sneeze them out which means they can not get into your lungs and make you sick. (This dirty slime can also slide down your throat, but if intruders get into your lungs, you could cough to get rid of them.)
Your mucus usually turns yellow when your body fights an infection.
If your mucus captures potentially pathogenic debris, such as pathogens that cause the common cold or flu your immune system sends inflammatory cells such as white blood cells into the area to destroy the invaders, Dr. Benninger explains. This inflammatory reaction – not the infective agents themselves – causes the signature to shift in mucus color, Dr. Benninger.
One of the first responders to microbial invaders is a type of white blood cell called neutrophils. Neutrophils are full of myloperoxidase (MPO), an enzyme that contains green-colored heme or iron. If these green neutrophils are over-concentrated, they can make your mucus appear green directly. If you are less focused, the mucus will appear pale green – but may look yellow to you instead.
You may also notice that your mucus has a deeper yellow color (or looks like it has disappeared.) From yellow to green) after several days of sickness, not brushing your nose for a while or if you are wake up in the morning. If the mucus sits in your nasal passages for a longer period of time, these inflammatory cells can build up and stain your mucus more intensively. Benninger. "The less you clear it, the more it will turn to color," he says.
So if you have yellow slime, you should often brush your nose to remove trapped debris and keep things moving.  Yellow slime is not necessarily a sign that you need to see a doctor.
What is really important is your accompanying symptoms and how long they are still there, Dr. Benninger. While you know your body better than anyone else, and if you feel unusually awful, you should go to the doctor, but it is good to know that some of the most common yellow phlegm diseases usually disappear without medication. For example, according to the Mayo Clinic refrigeration normally takes seven to ten days. A viral sinus infection usually begins to clear after five to seven days, while bacterial sinusitis can last for seven to ten days, hang longer, or even deteriorate by a week before finally disappearing, according to the Cleveland Clinic .
In the meantime, you can use OTC medications and home care to treat the symptoms of these types of diseases. The methods include anti-inflammatory agents for pain and fever, nasal rinsing and decongestants, if you have a particularly stuffy nose, Dr. Benninger. (However, you should not use decongestants that constrict your nasal blood vessels for more than three days, as this may overload the rebound. See .)
If you still feel like it After you've gotten sick on the shoe after about a week, you might want to see a doctor. You may need something like antibiotics to eliminate bacterial sinusitis. No matter what, your doctor can help diagnose the cause of your yellow slime and clear your snot crystal.