Coughing up mucus and phlegm from a chest infection from a virus and bacteria infection, looking at it under the microscope, with cells and microorganisms. Bacteria and skin cells close up

Illness, respiration and man coughing in a studio with asthma, virus or respiratory disease. Bacteria, germ and portrait of a sick male person with a flu, cold or chest infection by a gray background

Understanding Chronic Cough: Causes, Symptoms, and Diagnosis