Gastroesophageal reflux disease (GERD): This condition is characterized by the backflow of stomach acid into the esophagus, which can cause irritation and lead to vomiting of phlegm-like material.

Pneumonia or other respiratory infections: Infections in the lungs can cause an increase in mucus production, which may be vomited up.
Chronic bronchitis: This condition involves inflammation of the bronchial tubes, leading to excessive mucus production that can be vomited.
Asthma: Severe asthma attacks can cause coughing up of mucus, which may be vomited.

Aspiration pneumonia: This is a potentially life-threatening condition where food, liquids, or other materials are inhaled into the lungs, which can lead to a severe infection.
Pulmonary embolism: Although less common, a pulmonary embolism can cause sudden onset of symptoms including coughing up of blood or phlegm-like material.
Foreign body aspiration: Especially in children, aspiration of a foreign body can lead to severe respiratory distress and vomiting of phlegm.

Cystic fibrosis: A genetic disorder that leads to the production of thick, sticky mucus that can cause respiratory and digestive problems, including vomiting of phlegm.
Bronchiectasis: A condition where the airways of the lungs become abnormally widened, leading to excessive mucus production and potential vomiting.
Lung cancer: In rare cases, lung cancer can cause an increase in mucus production, which may be vomited, especially if the cancer is located in the central airways.