There is no proven therapy for cryptosporidiosis in persons with AIDS. Nitazoxanide appears to be a good candidate drug for further evaluation because of its effectiveness in preclinical models, the data from early clinical trials and its safety profile. Cooperation between clinical researchers and basic scientists in clinical trials of agents for HIV infection and its complications is a high priority for the ACTG, the NIAID, and the NIH. Thus, it is important to design a clinical trial of NTZ that includes cooperation with basic scientists.