The causes of salty phlegm are usually food-related and may also be due to respiratory infections, so please consult a doctor as soon as they are detected. 1. If you consume a large amount of high-salt food over a long period of time, it may cause the body fluids produced in the mouth or stomach to be salty because most of the components of the body fluids secreted by the human body are in the form of ions, so they usually contain a large amount of ions, such as sodium, potassium, chlorine, and calcium, which are combined to form a salty substance, ultimately leading to salty phlegm. 2. Certain common respiratory tract infections can also lead to salty sputum. Symptoms of respiratory tract infections usually include coughing, shortness of breath, and sputum, etc. Pathogenic bacteria cause necrotic substances to accompany sputum, which can result in sputum with a salty flavor. If you notice an increase in the amount of sputum, purulent sputum, blood in sputum, or a combination of other symptoms such as coughing and shortness of breath, it is recommended that you seek medical attention to avoid a delay in your condition.