Two-hundred-forty children, 6 to 17 years of age, were recruited to participate in the study. Following the collection of baseline data, all families in the study received standard environmental control education prior to randomization to the control or experimental group. This education provided parents and children with information about such topics as the child's sensitivity profile, the relationship between exposure to allergens and asthma, and the risks of passive smoking. All families were given information on how to receive environmental control aids and services available by mail at no or reduced costs.