Duyen, 33, developed bloodshot eyes after a five-minute severe coughing fit; doctors diagnosed a ruptured capillary causing subconjunctival hemorrhage in her right eye.

Smoking damages the respiratory tract, often manifesting as a persistent cough with phlegm and potentially an early sign of lung cancer.

Ms. Hang, 38, developed pulmonary tuberculosis, a diagnosis made after two weeks of coughing up thick yellow phlegm and blood led to her hospitalization.

I smoke, have had a dry cough for over a month, accompanied by chest pain, and medication hasn't helped. Could this be a sign of lung cancer? (Quoc Huy, 52, Can Tho)