Drinking more water is the single most effective way to loosen phlegm in your throat. In a study of people with postnasal drip, drinking one liter of water over two hours reduced mucus thickness by roughly 75%, and 85% of participants reported their symptoms improved. Beyond hydration, several other techniques can thin or move stubborn phlegm so you can clear it comfortably.
Why Hydration Works So Well
Mucus is mostly water, and when you’re even mildly dehydrated, it thickens and clings to the lining of your throat. Rehydrating does the opposite: it pulls water into the mucus layer and makes it slippery enough to move. Warm liquids like tea, broth, or plain warm water do double duty because the warmth itself helps loosen mucus on contact.
There’s no magic number of glasses per day that works for everyone, but a practical goal is to drink enough that your urine stays pale yellow. If you’ve been fasting, sleeping, or exercising, your mucus is likely thicker than usual, so front-loading fluids in the morning or after a workout can make a noticeable difference within an hour or two.
Salt Water Gargle
Gargling with salt water draws moisture out of swollen throat tissue and helps break up thick mucus. Mix about a quarter to a half teaspoon of table salt into 8 ounces of warm water. Take a mouthful, tilt your head back, and gargle for 15 to 30 seconds before spitting it out. You can repeat this several times a day without any downside.
The salt creates an osmotic effect, pulling fluid from the inflamed tissue while loosening the mucus sitting on the surface. Many people notice relief within minutes, though the effect is temporary. Doing it first thing in the morning, when throat mucus tends to be thickest, is particularly helpful.
Steam and Humid Air
Breathing in warm, moist air hydrates your airways from the inside. The simplest method is to lean over a bowl of hot water with a towel draped over your head, breathing slowly through your nose for five to ten minutes. A hot shower works the same way. Running a humidifier in your bedroom overnight can also prevent mucus from drying and thickening while you sleep.
If you use a humidifier, keep the humidity between 30% and 50% and clean the tank regularly. Stagnant water in a dirty humidifier can breed mold and bacteria, which would make throat congestion worse, not better.
The Huff Cough Technique
Forceful coughing can irritate your throat and actually trigger more mucus production. The huff cough is a gentler alternative that respiratory therapists teach to move phlegm up and out without the strain. Here’s how to do it:
- Sit in a chair with both feet flat on the floor and your chin tilted slightly up.
- Take a slow, deep breath until your lungs are about three-quarters full.
- Exhale forcefully in short bursts through an open mouth, like you’re trying to fog up a mirror.
- Repeat one or two more times, then follow with one strong cough to clear mucus from the larger airways.
Do this cycle two or three times, depending on how congested you feel. One important detail: avoid breathing in quickly or deeply through your mouth right after coughing. Quick inhalations can push mucus back down and trigger an uncontrolled coughing fit.
Positioning Your Body to Help Gravity
Lying flat lets mucus pool in your throat, which is why congestion often feels worse at night or first thing in the morning. Propping your head and upper body up with an extra pillow or a wedge keeps mucus draining downward rather than collecting at the back of your throat. Head-up positions are also safer and more comfortable than head-down drainage positions, which can cause acid reflux or discomfort.
If your congestion is mainly in your chest, lying on your side or stomach for short periods can help gravity pull mucus from different parts of your lungs toward your central airways, where it’s easier to cough out. Switching positions every 10 to 15 minutes covers more ground.
Over-the-Counter Expectorants
Guaifenesin is the active ingredient in most OTC expectorants. It works by thinning the mucus in your lungs and airways, making it easier to cough up. The standard adult dose for short-acting versions is 200 to 400 mg every four hours, and extended-release versions are typically 600 to 1200 mg every twelve hours. It won’t suppress your cough, which is the point. You want phlegm moving, not sitting still.
Guaifenesin works best when you’re also drinking plenty of fluids. Without adequate hydration, the medication has less raw material to work with, and mucus stays thicker than it should.
Dairy Does Not Increase Mucus
You may have heard that milk and cheese make phlegm worse. They don’t. Drinking milk does not cause your body to produce more mucus. What actually happens is that milk and saliva mix together in your mouth and create a slightly thick coating that lingers on your tongue and throat. That sensation gets mistaken for extra phlegm, but it passes quickly. A study in children with asthma found no difference in symptoms whether they drank dairy milk or soy milk. So if warm milk or a latte sounds soothing, go ahead.
When Phlegm Points to Something Else
Persistent throat phlegm isn’t always caused by a cold or allergies. One common culprit is laryngopharyngeal reflux, a form of acid reflux where stomach contents travel high enough to reach the throat. It often shows up as a constant feeling of something stuck in your throat, excessive mucus, and throat clearing, sometimes without the classic heartburn you’d associate with reflux. If your phlegm lingers for weeks and doesn’t respond to the usual remedies, reflux is worth considering.
The color of your phlegm also carries useful information. Clear or white mucus is typical of viral infections and allergies. Yellow or green phlegm suggests your immune system is actively fighting something, though it doesn’t automatically mean you need antibiotics. Most bacterial infections resolve on their own in 10 to 14 days, and viral infections can take up to three weeks. Red, pink, or bloody phlegm is a reason to see your provider, especially if you smoke.