What Does Grey Phlegm Mean?
Investigate the full background What Does Grey Phlegm Mean in this comprehensive guide.
Your phlegm may get thicker and darker as an infection progresses. It may also be thicker in the morning or if you are dehydrated. Clear phlegm that's associated with allergies is generally not as thick or sticky as the green sputum you see with bacterial bronchitis or the black phlegm from a fungal infection.