Cromolyn sodium (Intal) has been available in the United States to treat asthma for more than 30 years. Its clinical efficacy in patients with mild or moderate persistent asthma is well documented, and its extensive clinical record of safety remains unique among antiasthma medications. The history of cromolyn sodium complements the science behind current understanding of asthma pathophysiology. Cromolyn sodium was the first nonsteroid, antiasthma drug that blocked chemical mediator release at the cellular level. However, the younger generation of health care providers may not be familiar with the medication due to the plethora of antiasthma agents that have recently become available. This review reexamines the role of cromolyn sodium (now available as an HFA aerosol) in the treatment of asthma.