A series of amidines and sulfonamides of 5- and 6-amino-2,3-bis(4-alkyl-1-piperazinyl)quinoxalines was synthesized and tested against cecal and hepatic forms of Entamoeba histolytica infections in rats and hamsters, respectively. Four compounds (5, 6, 8, and 9) were found to have acceptable activity against infections in both species but were too toxic to be considered for use in man.