To examine the dose of zidovudine (AZT) that was used in the first placebo-controlled study of AZT in AIDS patients as well as a lower dose of AZT in order to determine if the lower dose results in less harmful side effects while still being effective. Previous studies have shown the effectiveness of AZT in AIDS therapy. AZT has been effective in test tube studies at varying doses. There is a need to see if lower doses result in effective therapy with less harmful side effects.