Phlegm that lingers in your throat is usually your body’s response to irritation, infection, allergies, or dry air. The fastest way to thin it out and move it along is a combination of staying well hydrated, gargling with warm salt water, and keeping the air around you humid. Most cases clear up within a week or two, but there are plenty of ways to speed things up and feel more comfortable in the meantime.
Why Phlegm Builds Up in Your Throat
Your airways are lined with a thin layer of mucus that traps dust, bacteria, and other particles before they reach your lungs. Tiny hair-like structures called cilia constantly sweep that mucus upward and out. When something irritates your respiratory tract, whether it’s a cold virus, seasonal allergies, acid reflux, or cigarette smoke, your body ramps up mucus production. At the same time, inflammation can slow the cilia down, so more mucus sits in your throat instead of being cleared away quietly.
Post-nasal drip is one of the most common culprits. Mucus produced in your sinuses drains down the back of your throat, creating that persistent feeling of something stuck there. This can happen with colds, sinus infections, allergies, or even changes in weather.
Drink More Fluids
Hydration is the single most effective way to thin phlegm. When your body is well hydrated, mucus stays at a low concentration of solids (around 2%), and the cilia in your airways can propel it efficiently. As mucus gets dehydrated and the solid concentration climbs to 3 or 4%, transport slows noticeably. At higher concentrations (7 to 8%), mucus essentially stops moving altogether and sticks to the airway walls.
Water, herbal tea, and warm broth all work. Warm liquids in particular can feel soothing and help loosen thick secretions. There’s no magic number of glasses per day, but if your urine is pale yellow, you’re likely drinking enough.
Gargle With Warm Salt Water
Dissolve half a teaspoon of salt in a glass of warm water and gargle for 15 to 30 seconds, then spit it out. The salt draws moisture out of swollen throat tissue, which reduces irritation, and it helps break up the mucus coating your mouth and throat. Salt also acts as a mild cleansing agent, flushing bacteria and viruses from the area. You can repeat this every few hours throughout the day.
Try Nasal Irrigation
If your phlegm is draining from your sinuses, rinsing them out with saline can make a big difference. A neti pot or squeeze bottle flushes mucus, allergens, and other debris directly out of the nasal passages, which means less of it ends up in your throat.
To make your own rinse, mix one to two cups of distilled or previously boiled water with a quarter to half teaspoon of non-iodized salt. Avoid tap water, which can contain organisms that are safe to drink but harmful when introduced directly into the sinuses. If you boil water, let it cool to lukewarm before use, and use it within 24 hours. Clean your neti pot or bottle after every use and let it air dry completely.
Skip nasal irrigation if you have an ear infection, pressure in your ears, a completely blocked nostril, or recent sinus or ear surgery.
Keep Indoor Humidity Between 40 and 60%
Dry air pulls moisture from your mucus membranes, thickening the mucus and making it harder to clear. Indoor humidity between 40 and 60% minimizes most respiratory irritation. A cool-mist humidifier in your bedroom can help, especially during winter when heating systems dry out indoor air. Clean the humidifier regularly to prevent mold and bacteria from growing in the water reservoir.
Elevate Your Head at Night
Lying flat lets mucus pool at the back of your throat, which is why phlegm often feels worse in the morning or when you’re trying to fall asleep. Sleeping with your head slightly elevated encourages drainage. Stack an extra pillow or slide a foam wedge under the head of your mattress. This is especially helpful if post-nasal drip is your main issue.
Use Honey for Cough and Irritation
A systematic review of multiple clinical trials found that honey outperformed standard care for relieving upper respiratory symptoms, including cough frequency and severity. A spoonful of honey on its own or stirred into warm tea coats the throat and can calm the irritation that triggers repeated coughing and throat-clearing. It’s widely available, inexpensive, and a reasonable first option before reaching for over-the-counter cough medicines. Don’t give honey to children under one year old due to the risk of botulism.
Over-the-Counter Expectorants
Guaifenesin is the active ingredient in most over-the-counter expectorants (products like Mucinex or Robitussin). It works by thinning mucus so your body can move it out more easily. Adults and children 12 and older typically take a dose every four hours, with a maximum of six doses in 24 hours. Drink a full glass of water with each dose to help the medication work. Extended-release versions are taken less frequently, so check the label for your specific product.
Expectorants help you cough mucus up more productively. If you’re also dealing with a runny nose, a decongestant may help reduce the amount of mucus draining into your throat, though these shouldn’t be used for more than a few days in spray form.
You Don’t Need to Avoid Dairy
The idea that milk makes your body produce more phlegm is one of the most persistent health myths around. Research has consistently shown that drinking milk does not increase mucus production. What actually happens is that milk and saliva mix to form a slightly thick coating in the mouth and throat, and that brief texture gets mistaken for extra phlegm. A study of children with asthma found no difference in symptoms whether they drank dairy milk or soy milk. So if a warm latte sounds comforting when you’re congested, go ahead.
What Phlegm Color Actually Means
Many people assume that green or yellow phlegm means a bacterial infection that needs antibiotics. The evidence doesn’t support this. A study in the Scandinavian Journal of Primary Health Care found that sputum color cannot reliably distinguish between viral and bacterial infections in otherwise healthy adults. Green and yellow mucus is a normal feature of viral bronchitis because the color comes from enzymes released by white blood cells fighting the infection, regardless of whether bacteria are involved.
Color does matter in certain situations, though. Red, pink, or brown phlegm can indicate blood, which sometimes signals a serious problem. Black mucus may point to a fungal infection, particularly in people with weakened immune systems. Frothy phlegm can be associated with heart or lung conditions. Any of these warrant prompt medical attention.
When Phlegm Signals Something Bigger
Most throat phlegm from a cold or mild allergy clears up on its own within one to two weeks. Contact your doctor within a few days if your mucus comes with fever, chills, persistent coughing, or sinus pain. If you have asthma, allergies, or a chronic lung condition, let your doctor know about any noticeable increase in mucus production or changes in its color or texture.
Seek immediate attention if you cough up red, brown, black, or frothy phlegm, or if you develop new shortness of breath or chest pain alongside a change in your sputum. These combinations can indicate a lung or heart problem that needs evaluation right away.