It is our purpose in this paper to present our clinical observations over a period of five years on 406 patients harboring one or more of the five forms of human intestinal ameba. These patients represent a cross section of the types of cases and complaints usually encountered in a gastrointestinal clinic. They were all given antiamebic treatment and the results are here recorded. This study is also intended to emphasize:
the lack of uniformity in the observations made by various workers 1 in this field;
the greater incidence of all types of intestinal ameba in man than is generally recognized;
the responsibility of protozoa other than Endamoeba histolytica for the symptoms produced;
the advisability of classifying all forms of ameba as potential pathogens, since they probably are capable of producing, to a moderate degree, many of the same symptoms produced by E. histolytica.