Menu Healthy Lifestyle Diseases & Conditions First Aid Symptoms Tests & Procedures Videos Definitions FAQs PhlegmUpdated: 2018-05-26Self-careDrink warm fluids, and moisturize the air with a vaporizer or a steamy shower to help thin mucus. Drugs containing guaifenesin (Mucinex, Robitussin, others) can reduce phlegm. When to seek immediate medical careSee a doctor immediately if: Breathing is difficult Phlegm is mainly blood When to make a doctor's appointmentMake an appointment to see a doctor if: Greenish-yellow or gray phlegm Phlegm is pink-tinged or contains blood Wheezing or cough Fever above 100 F (38 C) Help quitting smoking needed © 1998-2022 Mayo Foundation for Medical Education and Research(MFMER). All rights reserved. Terms of Use