Diclazuril (R-64433) is an anti-coccidial drug. IC50 & Target: Antiparasitic^[1]. In Vivo: Diclazuril (R-64433) is a coccidiostat, the lambs treated with diclazuril showed an intense, persistent oocyst excretion, with average levels of 97.54 opg, considerably higher than those recorded in the animals treated with toltrazuril (p < 0.05)^[1]. Diclazuril (R-64433) is effective against E. maxima later in its life cycle, subclinical intestinal lesions may be present for a short time after infection. Diclazuril (R-64433) was shown in studies to reduce lesion scores and improve performance and health of birds challenged with E. maxima^[2].