INVESTIGATING the antihistomonal activity of 1,2-disubstituted-5-nitroimidazoles in turkeys, Mitrovic et al. (1968) concluded that among the various derivatives tested, ipronidazole, 1-methyl-2-isopropyl-5-nitroimidazole, was the most effective. Subsequent reports by Marusich et al. (1970a, b) showed it to be a drug of remarkably low toxicity and high safety which, in addition, possesses growth promoting activity with improved feed utilization when fed to turkeys.Prompted by these interesting observations, detailed laboratory studies on the efficacy of ipronidazole against experimentally induced histomoniasis in turkeys were carried out and are the object of this report.MATERIALS AND METHODSExperimental design. Two-week-old Broad Breasted White turkey poults, kept in wire floor batteries and housed in thermostatically controlled rooms, were used throughout the experiments. Ten birds selected according to weight and sex (50% F and 50% M) were used per each group, and each trial, in most cases, repeated 4 to 8 times. Turkey starter mash, a…