<P> Phlegm / ˈflɛm / ( Greek : φλέγμα `` inflammation , humour caused by heat '' ) is a liquid secreted by the mucous membranes of mammals . Its definition is limited to the mucus produced by the respiratory system , excluding that from the nasal passages , and particularly that which is expelled by coughing ( sputum ) . Phlegm is in essence a water - based gel consisting of glycoproteins , immunoglobulins , lipids and other substances . Its composition varies depending on climate , genetics , and state of the immune system . Its color can vary from transparent to pale or dark yellow and green , from light to dark brown , and even to dark grey depending on the constituents . </P>
<P> Phlegm / ˈflɛm / ( Greek : φλέγμα `` inflammation , humour caused by heat '' ) is a liquid secreted by the mucous membranes of mammals . Its definition is limited to the mucus produced by the respiratory system , excluding that from the nasal passages , and particularly that which is expelled by coughing ( sputum ) . Phlegm is in essence a water - based gel consisting of glycoproteins , immunoglobulins , lipids and other substances . Its composition varies depending on climate , genetics , and state of the immune system . Its color can vary from transparent to pale or dark yellow and green , from light to dark brown , and even to dark grey depending on the constituents . </P>
where does the phlegm in your throat come from
where does the phlegm in your throat come from
mucus produced by the respiratory system
mucus produced by the respiratory system