Definition of phlegm in US English:



  • 1The thick viscous substance secreted by the mucous membranes of the respiratory passages, especially when produced in excessive or abnormal quantities, e.g., when someone is suffering from a cold.

    • ‘Our purpose was to identify the following major symptoms of chronic respiratory airways diseases: chronic cough, chronic phlegm, dyspnea, and wheezing.’
    • ‘A cough is a reflex action to clear the airways of mucus, phlegm, irritants or a foreign body.’
    • ‘You may begin with a dry cough, then produce phlegm as the cold progresses.’
    • ‘A coughing fit brought up some more thick phlegm.’
    • ‘You've probably seen - and heard - them in the gym: people sniffling, sneezing, coughing up phlegm.’
    • ‘COPD (similar to chronic bronchitis) is a disease which narrows the airways, causing excessive amounts of phlegm to be produced and causes shortness of breath in its later stages.’
    • ‘Several respiratory symptoms among plywood workers have been found, including cough, phlegm, asthma, chronic bronchitis, and chest colds.’
    • ‘This herb should not be used by those with wind cold conditions such as the common cold when there is phlegm nor should it be used when there is Spleen deficiency with diarrhea.’
    • ‘As a result, they can't cough out phlegm and sometimes develop respiratory infections that can quickly become serious.’
    • ‘Drinking lots of fluids, especially water will help to reduce phlegm and mucus.’
    • ‘Production of phlegm, shortness of breath, and wheezing were significantly more prevalent in exposed than in reference subjects.’
    • ‘However, susceptibility to respiratory morbidity varies among smokers and chronic cough and phlegm production and other respiratory-related morbidity occur in nonsmokers.’
    • ‘Wheeze is just one of a constellation of common respiratory symptoms, including cough, phlegm, and shortness of breath.’
    • ‘In a comparison of a low-pollution rural and a high-pollution urban area in Italy, the residents of the latter had a greater prevalence of respiratory symptoms, except chronic phlegm.’
    • ‘When they are irritated they narrow, the muscles around them tighten, and there may be an increase in production of sticky mucus or phlegm.’
    • ‘During this time, active smoking decreased, particularly in men, as well as slightly did the prevalence of respiratory symptoms, such as phlegm and cough.’
    • ‘Children exposed to secondhand smoke are also more likely to have reduced lung function and symptoms of respiratory irritation like cough, excess phlegm, and wheeze.’
    • ‘Acute bronchitis is a clinical diagnosis designating an acute respiratory tract infection in which cough, with or without phlegm, is a predominant feature.’
    • ‘The remedy has a particularly potent curative effect on chronic bronchitis, coughs, and asthma due to excessive phlegm.’
    • ‘If the disease progresses and cavities form in the lungs, the person may experience coughing and the production of saliva, mucus, or phlegm that may contain blood.’
    mucus, catarrh, mucous secretion
    View synonyms
    1. 1.1 (in medieval science and medicine) one of the four bodily humors, believed to be associated with a calm, stolid, or apathetic temperament.
      • ‘According to humoral theory, the body comprised of the four humours blood, phlegm, choler, and melancholy; and pathological conditions are the result of humoral abnormalities.’
      • ‘According to this theory, the most important determinants of health were the four humours found in the body: blood, phlegm, black bile, and yellow bile.’
      • ‘Illness, according to Galen, was caused by an imbalance of the body's four humors: blood, phlegm, yellow bile, and black bile.’
      • ‘Our bodies were thought to be composed of blood, phlegm, black bile, and yellow bile just as the world at large consisted of earth, air, fire, and water.’
      • ‘An example is the belief, originating in classical times, that disease is caused by an imbalance among four bodily humors: blood, phlegm, yellow bile, and black bile.’
    2. 1.2 Calmness of temperament.
      ‘phlegm and determination carried them through many difficult situations’
      • ‘Phlegm (taken in a good sense) is the temperament of cold reflection and perseverance in the pursuit of one's end.’
      • ‘Immigrants living among people from the same country in a kind of ghetto therefore have no incentive to overcome their phlegm and finally learn German.’
      self-control, calmness, calm, coolness, composure, sangfroid, level-headedness
      View synonyms


Middle English fleem, fleume, from Old French fleume, from late Latin phlegma ‘clammy moisture (of the body)’, from Greek phlegma ‘inflammation’, from phlegein ‘to burn’. The spelling change in the 16th century was due to association with the Latin and Greek.