Inclusion Criteria

Patients must have:

• AIDS diagnosis according to CDC criteria.
• CD4 count less than or equal to 200 cells/mm3 or CD4 count greater than or equal to 200 cells/mm3 and documented cryptosporidiosis for a minimum of 4 weeks.
• Cryptosporidial diarrhea as defined by:
• (1) presence of Cryptosporidium oocytes in a stool specimen within 14 days of enrollment; and (2) chronic diarrhea (i.e., an average of at least 4 bowel movements per day for a minimum of 2 weeks).
• Life expectancy of at least 1 month.
• Ability to tolerate food by mouth.

Prior Medication:

Required:

• Any anti-diarrheal or anti-emetic medication for which the dosage regimen has been stable for at least 1 week prior to enrollment.
• Any antiretroviral medications (e.g., zidovudine, ddI, ddC) for which the dosage regimen has been stable for at least 3 weeks prior to enrollment.

Allowed:

Medication for prophylaxis or maintenance therapy of opportunistic infection, stable for at least 2 weeks prior to enrollment.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

Grade 4 (hematologic) or Grade 3 (for all others) toxicity. (Patients with Grade 3 toxicity for hepatic parameters may be enrolled if, in the investigator's judgment, the abnormalities are due to biliary cryptosporidiosis.)

Patients with the following prior conditions are excluded:

• Presence of Salmonella, Shigella, Campylobacter, Yersinia, Giardia lamblia, Entamoeba histolytica, Microsporidia, Isospora, Cyclospora, or Clostridium difficile toxin in stool (based on assessment within 14 days prior to enrollment by stool ova and parasite examination, culture, and C. difficile assay).
• History of intestinal Mycobacterium avium intracellular infection or intestinal Kaposi's sarcoma.
• History of Cytomegalovirus colitis, unless 28 days of therapy with ganciclovir or foscarnet completed subsequent to diagnosis.

Prior Medication:

Excluded:

• Investigational drug therapy within 14 days of enrollment, unless available under an FDA-authorized expanded access program.
• Any drug or therapy with possible anticryptosporidial activity (e.g., paromomycin, spiramycin, azithromycin, clarithromycin, hyperimmune bovine colostrum) within 14 days of enrollment.