Exclusion Criteria

Co-existing Condition:

Patients with the following are excluded:

• Severe ongoing opportunistic infection including Pneumocystis carinii pneumonia (PCP), cryptococcal or toxoplasmosis meningoencephalitis, disseminated herpes simplex or herpes zoster. A demonstrated prior sensitivity or an experience of significant adverse effects during prior therapy with the drug to be used in the study.
• Significant diarrhea at entry ( > 1 watery stool/day).

Patients with the following are excluded:

• Severe ongoing opportunistic infection including Pneumocystis carinii pneumonia (PCP), cryptococcal or toxoplasmosis meningoencephalitis, disseminated herpes simplex or herpes zoster. A demonstrated prior sensitivity or an experience of significant adverse effects during prior therapy with the drug to be used in the study.
• Significant diarrhea at entry ( > 1 watery stool/day).

AIDS related complex (ARC) defined as presence of any one of the following within 12 months prior to entry and absence of a concurrent illness or condition other than

HIV infection to explain the findings:

• Fever of > 38.5 degrees C persisting for longer than 3 weeks.
• Involuntary weight loss of > 15 lbs. or > 10 percent of baseline noted in a 120-day period prior to evaluation.
• History of diarrhea (> 2 liquid stools per day) persisting for longer than 1 month but not occurring at entry.
• History of clinical diagnosis of oral candidiasis or hairy leukoplakia. Patients who have AIDS-defined opportunistic infections or tumors.
• Patients eligible for zidovudine under the labeling. A positive HIV antibody test. Exceptions will be made for patients with a previously positive HIV antibody test with progressive disease and patients where virus isolation has been made. A life expectancy of at least 3 months.
• Patients with stable Kaposi's sarcoma, mild herpes infections, mild or stable depression, asymptomatic or mild cytomegalovirus or Epstein-Barr virus infection, or a hepatitis B virus carrier state will be acceptable for study.

Inability to abstain from alcohol or any other drug, including nonprescription medications, during the study period.