Is Mucinex Safe To Take When Breastfeeding?
In our latest question and answer, our pharmacist discusses whether or not Mucinex is safe to take if you are breastfeeding.

Question
Hello. I'm breastfeeding and am wondering if Mucinex is safe to use.

Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist
Staff
Last updated Apr 23, 2025
Key points
- Most resources state that Mucinex (guaifenesin) is safe to use while breastfeeding, even though comprehensive information on how much is excreted into breastmilk isn't available.
Answer
Hello and thank you for your question! We're more than happy to answer this for you.
Overall, most sources state that Mucinex (guaifenesin) is considered safe to use while breastfeeding, even though there is a lack of clinical studies that have evaluated the drug in this manner.
Two of the most widely cited sources, 'LactMed' and Dr. Hales 'A Manual of Lactational Pharmacology' consider Mucinex safe to use in breastfeeding mothers.
LactMed Recommendation
The National Institute of Medicine's database, 'LactMed', is a comprehensive resource on drugs and breastfeeding that states the following:
Neither the excretion of guaifenesin in milk nor its effect on breastfed infants have been studied. It is unlikely that with usual maternal doses amounts in breastmilk would harm the nursing infant, especially in infants over 2 months of age. It is best to avoid the use of products with a high alcohol content while nursing.
'A Manual of Lactational Pharmacology Recommendation''
One widely cited and respected resource, Hale's Medications & Mothers' Milk 2021: A Manual of Lactational Pharmacology, written by Dr. Thomas Hale, categorizes drugs into safety categories (L1-L5).
These categories are:
L1 Safest: Extensive evidence demonstrating no adverse effects on the infant
L2 Safer: Limited evidence without an increase in adverse effects on the infant
L3 Probably Safe: No studies, but expert opinion suggesting safety. Risk to the infant is possible, and further evaluation must be taken to consider individual situations.
L4 Possibly Hazardous: Positive evidence or expert opinion of risk to the infant or milk production.
L5 Hazardous: Significant and documented risk to the infant.
Dr. Hale assigned Mucinex (guaifenesin) to category L2 (safer). Again, comprehensive data on how much guaifenesin is excreted in breastmilk is not available, but no adverse effects in infants have been recorded. Similarly, there are no case reports of side effects in infants who were breastfed by mothers taking guaifenesin.
Final Words
It is important to speak to your doctor regarding what medications are safe for you to take while breastfeeding. All available information points to Mucinex being safe, but your doctor knows your medical situation best and can provide the most appropriate guidance for you.
References
- Guaifenesin Monograph, Drugs and Lactation Database (LactMed) [Internet].
- Use of cough and cold preparations during breastfeeding, PubMed
- Hale's Medications & Mothers' Milk - 2021 A Manual of Lactational Pharmacology, Google Books
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Dr. Brian Staiger, PharmD
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