Over the past two decades, scientific evidence has shown that the combination of cockroach allergy and cockroach exposure is one of the most important factors contributing to the dramatic increase in asthma morbidity seen in inner city children with asthma. Therefore, a major goal of the National Institute of Allergy and Infectious Diseases (NIAID) Inner City Asthma Consortium (ICAC) is ultimately to conduct a large multi-center trial of cockroach sublingual immunotherapy (SLIT) in inner-city asthma. As a step toward achieving this goal, ICAC is conducting a clinical trial comparing two doses of glycerinated German cockroach (Blattella germanica) allergenic extract to placebo, administered under the tongue (sublingual).