What is the Difference Between a Decongestant and Expectorant?

Jessica Ellis
Jessica Ellis

Decongestant and expectorant are common terms found when obtaining medication to treat respiratory problems such as colds, infections, and allergies. While the medications are often packaged together, they each use different methods to manage the symptoms of a respiratory illness. It is important for patients to remember that, while both medications can help reduce inflammation and relieve symptoms, neither is a cure for an underlying illness.

An expectorant helps a person to cough up phlegm more easily.
An expectorant helps a person to cough up phlegm more easily.

There are several differences between a decongestant and expectorant, including what part of the respiratory system is treated. Decongestants reduce swelling in the nasal passages, helping to relieve a stuffy nose, sinus headache, and decreased hearing due to excess phlegm in the area. It makes phlegm in the nose and throat runnier, making it easy to expel.

Decongestants are better at reducing swelling, and therefore relieving the symptoms of, a sinus headache.
Decongestants are better at reducing swelling, and therefore relieving the symptoms of, a sinus headache.

The possible confusion between the two has to do with the increase of mucus or phlegm expulsion that is common with both medications. Instead of treating the nose and throat, an expectorant attacks phlegm in the lungs. They are often used to treat upper-respiratory infections, bronchitis, or pneumonia. By loosening the phlegm in the lungs, an expectorant helps a sick person cough up the mucus and breathe easier.

Prescription decongestants.
Prescription decongestants.

Both decongestant and expectorant properties are found in combination drugs meant to treat colds. Despite appearing in the same dose, it is important to remember that they are separate medications meant to treat different symptoms. Decongestant-related products typically contain one of two drugs: pseudophedrine or the more mild phenylephrine, though some topical or spray forms use a different drug called oxymetazoline. Expectorant medications derive most commonly from the drug guaifenesin.

Phlegm that is coughed up should be spit out, not swallowed.
Phlegm that is coughed up should be spit out, not swallowed.

For those who prefer natural remedies, there are alternative though separate versions of both decongestant and expectorant medications. Syrup of ipecac has been a folk remedy version of an expectorant for centuries, and was often used to treat whooping cough and bronchitis before the advent of modern drugs. Exposure to strong spices, onions, or snorting saltwater can all cause a temporary decongestant effect.

Expectorant are usually found in cough syrup.
Expectorant are usually found in cough syrup.

Over-the-counter combination drugs that have both medications are extremely common, but not always necessary. Since side effects such as drowsiness tend to increase as more medications are added to a dose, it's usually best for patients to take only the medicine that addresses their specific symptoms. If a person has a cold that does not include coughing, an expectorant may be unnecessary and may increase the risk of side effects. For serious conditions, medical professionals may prescribe drugs that provide a higher dose of necessary medications.

Decongestant nasal spray may cause mild nose bleeding as a side effect.
Decongestant nasal spray may cause mild nose bleeding as a side effect.
Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a wiseGEEK writer.

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Discussion Comments


For those referring to bronchitis and a hacking cough I suggest you also look up bronchiectasis. Don't jump to conclusions though -- it is only confirmed by CT chest scan with contrast. It can be intense or mild, depending on whether it is the widespread or specific type B/E, and there are three types of it.


Read the labels of your own medications, of course, but my experience has been that nasal decongestants keep me awake, and that antihistamines put me to sleep.

I take nasal decongestants during the morning hours to "de-clog" my nose, and antihistamines before I go to bed to "dry up" my nose, and also so I can fall asleep.

I've never taken an expectorant. My colds and flus have never gotten that serious.


If you are looking for an alternative to over the counter expectorants, try a boiling pot of water. This sounds too simple to be effective, but it really works.

I had a horrible cough due to chest congestion. I boiled some water and held my head over the pot. I draped a towel over both my head and the vigorously boiling water, and this trapped the steam inside so that I could deeply inhale it.

Fortunately, this also works for those of you who need a decongestant. It can clear up your nasal passages, too.


The decongestants in cough syrup often make me too drowsy to function. Since I usually go to work even if I have a cold or sinus issue, this is not an option for me.

I decided to try a eucalyptus salve instead. I rubbed some under my nose, and it opened up my sinuses enough for me to breathe a little. I kept it with me at work and reapplied it periodically.

At home, I put some of this salve into my humidifier and turned it on. It produced warm vapors with a strong, sinus opening aroma.


@ddljohn – I know what you mean. I once took some cough syrup that I thought would give me a break from the incessant hacking, but it only made it more intense. Only after that did I notice that it was labeled “expectorant.”

So, I switched to a decongestant with a cough suppressant in it. Perhaps I would have gotten over my bronchitis sooner if I had taken the expectorant, but like you, I could not tolerate the excessive coughing. My lungs literally hurt from the strain.

Luckily, I was also on steroids, so that helped me get over the illness. The steroids do have side effects, but they are more tolerable than those of the expectorant.


When I have a cold, a decongestant is the best thing for me to take. However, it makes my already runny nose run even more.

I usually get really stuffed up, but ironically, mucus is also oozing constantly out of my nose. I can't breathe through it, because it is swollen, but nothing seems to be trapped inside, because it is all coming out!

The decongestant does let me breathe a little bit through my nose, although it doesn't totally dry things up. After I blow a lot of the mucus out, I find that I have a small opening in my airways that lasts for about four hours, until I am due for more decongestant.


Something interesting about over the counter expectorants is that they have uses in home fertility treatment!

During a woman's fertile period of the month, she should have cervical fluid (visible as vaginal discharge) that is smooth and stretchy, like egg whites. It is important that this mucus be present, as it helps the sperm to travel all the way to the Fallopian tubes, where the egg is waiting to be fertilized.

Well, some women ovulate on time, but their cervical fluid is thick and sticky. They can try taking an expectorant (the same one that's in Robitussin -- name brand is not important but you want no letters; it should be plain expectorant, no decongestant or antihistamine). Since an expectorant thins all the body's secretions, it can thin out the cervical fluid and make it more hospitable, thus helping conception to take place.


@ddljohn, @fify-- I agree with both of you. Decongestants don't actually get the mucus out. I think it's more of a preventive measure rather than a treatment.

As far as I know, decongestants work by shrinking blood vessels in the nose tissues that produce mucus. So it will clear up the nose passage and prevent more mucus production. But if you have mucus elsewhere, like the lungs, it doesn't work for that. (That's why it's usually called a "nasal decongestant.")

So it doesn't make sense to take a decongestant for cough and it doesn't make sense to take an expectorant for a stuffy nose.


@ddljohn-- That's actually normal because coughing is how the lungs get rid of mucus which is how an expectorant works.

There are however expectorant and cough suppressant medications available. This is a two-in-one, so while you get rid of the mucus in the lungs, you're not "coughing your lungs out."

Decongestants work too obviously. But when you're dealing with a serious respiratory infection that has lasted for a while, an expectorant is going to be better.


Once I took expectorant medication when I had a severe cold and cough. Oh my god! That medication made me cough my lungs out! I have never taken an expectorant since!

The way I see it, a decongestant helps prevent mucus building up in the nose and sinuses but an expectorant makes you cough up all the mucus in the system. I don't think one is necessarily better but the results of taking an expectorant is far more intense than a decongestant from my experience.

I take an over the counter decongestant whenever I have a sinus infection but it has never worn me out like an expectorant has.

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