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.


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

Asked by Lindy On Aug 11, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Aug 11, 2022
Last updated Sep 29, 2023

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.


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.


About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at! You can also connect with Dr. Brian Staiger on LinkedIn.

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