1. Definition >    2. Symptoms >

Asthma is a disease of the lungs -- specifically of the small airways, called bronchioles, which become narrowed, inflamed, and choked with mucus. This bronchiole blockage causes the breathing problems that occur in asthma.

MEDICAL REVIEW: Reviewed by Michael W. Smith, MD, May 2004

SOURCE DOCUMENTATION: Scientific American Medicine, The Merck Manual, 17th edition

LEGAL DISCLAIMER: This tool is for general information purposes only and does not address individual circumstances. It may not be right for you and should not be relied upon in making decisions about you health. Always consult your doctor for medical advice.