Experience with beclomethasone dipropionate during the past 5 years has confirmed and extended the original observation that it is an effective, topically active corticosteroid of great value in treating asthma. Most steroid-dependent asthmatic patients can be successfully controlled with the drug, at least most of the time, and the therapeutic effect is dose dependent. Although high doses may be associated with some adrenal suppression such doses do not cause systemic symptoms, and side effects are of little consequence. It is important that patients treated with steroid aerosols continue to receive other effective therapeutic agents, notably adrenergic drugs, particularly by aerosol, and theophylline compounds; that they learn how to inhale the aerosol properly; and, most important, that they promptly start taking oral steroids when they experience an exacerbation of asthma.