Acute bronchitis is a lower respiratory tract infection in which the bronchial tubes, the larger airway of the lungs, become inflamed and filled with mucus. Viral infections account for the majority of acute bronchitis cases, whereas bacterial infections are uncommon. Upper respiratory tract infections, like the common cold, can sometimes lead to acute bronchitis.[1][2]
What is acute bronchitis?
Written by:
Fact-checked
by:
•Last Updated: May 16, 2025
Acute bronchitis is a lower respiratory tract infection characterized by inflammation and mucus buildup in the bronchial tubes, primarily caused by viral infections. It can sometimes develop after upper respiratory tract infections such as the common cold.