Everything You Need to Know About Expectorants

If you have a nagging cough or mucus buildup in your chest that just won't go away, an expectorant may be just what you need. Expectorants can relieve chest congestion caused by respiratory illnesses such as the flu, a cold, or bronchitis, which often cause excessive thick mucus (phlegm), and lead to congestion, coughing, or general chest discomfort. Expectorants help thin and loosen the mucus, making it easier to cough it out of your lungs, airways, or throat. 

Keep reading to find out how they work, the types of expectorants, potential side effects, drug interactions, and natural alternatives. 

A mixed-race woman blowing her nose

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How Do Expectorants Work? 

Having some mucus in your respiratory tract is normal and healthy. Mucus hydrates the airways and protects against germs.

However, when germs and bad bacteria enter your airways, your body makes extra mucus to trap them and cough them out. Immune system cells join the fight, making mucus extra thick and sticky. This thick mucus can cause friction and make your airways swell up, which in turn, can trigger the airway glands to make even more mucus. 

Sometimes this thick mucus gets stuck, and you can’t cough it out. Expectorants work by thinning the mucus, lubricating the airways, and loosening trapped mucus so that your cough is more productive, and you can cough the mucus out. 

Different Types of Expectorants

Expectorants come in various forms, including over-the-counter (OTC) medications, prescriptions, and natural remedies. 


Guaifenesin, also known as glyceryl guaiacolate, is a medication that you can buy in generic or brand versions. You can get it over-the-counter (OTC) or as a prescription. Common brand names include Mucinex and Robitussin. Guaifenesin comes in pill, tablet, granular, and liquid forms.

You can take it by itself or find it in combination cold, flu, and cough medications with cough suppressants, decongestants, antihistamines (allergy medicine), and analgesics (pain and fever reducers). 

Examples of combination medications include: 

  • Tylenol Sinus Severe (guaifenesin/acetaminophen/dextromethorphan)
  • Mucinex Sinus-Max Pressure & Pain (guaifenesin/acetaminophen/dextromethorphan)
  • Sudafed Head Congestion & Mucus (phenylephrine/acetaminophen/guaifenesin)

When taken as directed, guaifenesin is generally safe and well-tolerated. However, it’s important to note the following safety tips before taking any OTC medications:

  • Ask your healthcare provider or pharmacist about drug interactions 
  • Ask your healthcare provider if the medication could worsen your health conditions
  • Carefully read the labels and check the ingredients
  • Avoid duplicate ingredients such as Tylenol (acetaminophen)
  • Take caution when driving or operating heavy machinery

Potassium Iodide

Potassium iodide is a prescription expectorant. Healthcare providers prescribe it for those who have chronic lung diseases such as asthma or emphysema. 

Natural or Herbal Expectorants

Here are some natural ways that may be effective in helping to treat your cough:

  • Menthol: Menthol is from the mint plant family. You can find it in peppermint tea, cough drops, syrups, rubs, and vapors. 
  • Licorice root: This expectorant soothes airways while loosening and thinning mucus. 
  • Thyme and primrose extract: Studies show that thyme and primrose extracts behave as expectorants. Bronchosol is an example of an expectorant syrup that contains these two ingredients.
  • Ivy leaf extracts: One systematic review notes that Ivy leaf (Hedera helix) preparations are safe to use for coughs. However, they note that more research is needed to determine effectiveness. 
  • Water: Drinking plenty of water hydrates the mucus and thins it out, helping it to get out of the airways. 

How To Take Oral Expectorants

Oral expectorants come in pills, tablets, granules, or syrups that you take by mouth. Most begin to work about 15 to 30 minutes after taking them.

Always read the label carefully and follow the instructions for how to take them. Take expectorants with a full glass of water. 

The dose and frequency of the expectorant depends on your age and health conditions. So, it's important to follow your healthcare provider's instructions before you take it. For best results, take it consistently and finish the entire course of medication as prescribed.

If you are taking a liquid or syrup expectorant, shake it well and measure it with a measuring cup or oral syringe. A household spoon does not provide the correct dose. If you are using a syringe or cup, rinse it out after each use and keep it in a clean place. 

The following safety tips can help ensure that your oral expectorant treatment is safe and effective. 

  • Don’t split pills or tablets unless directed by a healthcare provider or pharmacist.
  • Do not crush or chew pills and tablets.
  • Stay hydrated by drinking plenty of water.
  • Notify your healthcare provider if you have a persistent cough lasting more than seven days.
  • Notify your healthcare provider if your cough is accompanied by a rash, fever, or severe persistent headache.
  • When taking guaifenesin, do not exceed 2400 mg/day. 

Possible Side Effects

Experiencing side effects with guaifenesin is rare. If they occur, they are typically mild and include:

  • Nausea and vomiting (most common)
  • Dizziness 
  • Headache
  • Rash 
  • Urticaria (itching)
  • Drowsiness (especially when included in combination medication)

Serious adverse effects such as kidney stones related to guaifenesin are rare. They are usually due to overdose or when taken as a combination medication. 

Taking potassium iodide can cause:

  • Stomach problems
  • Rash
  • Swollen or tender salivary gland

More rarely, potassium iodide may cause:

  • Confusion
  • Irregular heartbeat
  • Numbness or tingling
  • Pain in hand or feet
  • Tiredness or weakness
  • Swelling in the throat
  • Thyroid problems

Possible Drug Interactions

There are no known drug interactions for guaifenesin. However, double-check with your healthcare provider or pharmacist regarding combination drugs. Other ingredients may have drug or food interactions. Guaifenesin should not be given to children less than 12 years old. 

If you are pregnant or breastfeeding, you should only take guaifenesin after consulting with your healthcare provider about the risks and benefits associated with its use during pregnancy and lactation. 

Ask your healthcare provider or pharmacist about drug interactions when taking potassium iodide. It can negatively interact with multiple medications, including lithium and antithyroid medications. 

Avoid taking potassium iodide with other potassium-containing medications, potassium-sparing diuretics, and angiotensin-converting enzyme inhibitors (ACE inhibitors). Taking these medications together could result in cardiac arrest. 

If you are pregnant, you should avoid potassium iodide, since it can cause harm to your baby. If you are breastfeeding, talk with your healthcare provider, since it can cause a skin rash and thyroid suppression in breastfeeding infants. 

When it comes to herbal and natural remedies, always discuss with your healthcare provider. Herbs can also interact with prescription and OTC medications.

A Quick Review

Expectorants are an effective way to clear mucus in the airways and throat. With many different types and natural options available, you can find an expectorant that fits your needs. Many come in combination cold and flu medications, so be aware of duplicate ingredients.

Always take expectorants as your healthcare provider instructs you for maximum safety, effectiveness, and symptom relief. It’s important to be aware of potential side effects, interactions, and contraindications when taking expectorants. 

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11 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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