To establish the relationship between the oral dose of zidovudine (AZT) and its hematologic toxicity. AZT has preliminarily been shown to decrease significant events and death in a group of AIDS / Pneumocystis carinii pneumonia (PCP) and AIDS related complex (ARC) patients followed at this time for a limited period. If these data withstand further follow-up, it appears that AZT is a potential antiretroviral agent that may have application in the use of all stages of HIV disease. At this time the optimal dose that will not cause significant toxicity is not known. If this drug has widespread application, it becomes imperative to further study both the dose and the toxicity. Patients with documented HIV viremia and who are well will be evaluated in a dose-escalating protocol for toxicity, persistent viremia, evidence of improvement of immune dysfunction, and the development of further manifestation of HIV disease. Drug levels will be monitored and correlated with the toxicity and viremia.