👉 Phlegmatous is a medical term that describes a condition characterized by excessive mucus production in the upper respiratory system. It can be caused by various factors such as allergies, asthma, or chronic obstructive pulmonary disease (COPD). In some cases, phlegmatous may also indicate an underlying lung disorder such as emphysema. Phlegmatous is often associated with coughing and difficulty breathing due to the mucus in the airways.