Human infection with the intestinal protozoan Coccidium1 is rare. Magath2 reviewed 208 authenticated cases, approximately three fourths of which were found during World War I among soldiers in the eastern Mediterranean, and an additional 25 cases have been recorded to date. Although infection usually does not give rise to symptoms, reports in the literature mention diarrhea, abdominal pain, lassitude and slight weight loss in association with coccidiosis. In contrast to the hemosporidia, the malarial parasites, coccidia of the human bowel, Eimeria and Isospora have not been proved pathogenic for man, although Priest3 assumes cell destruction and invasion of intestinal epithelium by Isospora. The organism has never been found in intestinal tissue, and no specific lesion has been demonstrated. Many therapeutic agents have been used, including bismuth, iodide, quinine, gentian violet, emetine, anthelmintics and others without conclusive evidence of results. The oocyst, the stage of development usually seen in fresh stool