Guaifenesin is an expectorant that helps thin and loosen mucus in the chest , so it’s easier to cough up and clear from your airways.

Quick Scoop

It’s commonly used for chest congestion from colds, flu, bronchitis, and similar respiratory illnesses. By making mucus less sticky, it can make coughs more productive and help you breathe more comfortably.

Common Side Effects

Most people tolerate it well, but possible side effects include:

  • Headache.
  • Nausea or vomiting.
  • Dizziness.
  • Stomach upset or diarrhea.

When to Get Help

Get medical help right away if you have signs of a serious allergic reaction, such as rash, hives, swelling, trouble swallowing, or breathing problems.

If you want, I can also explain how to take it , whether it works for a wet vs. dry cough , or how it differs from dextromethorphan.