There are two mode of action of every anticoccidial drugs.1) self chemical action of Emeria spp. For example Toltrazuril Toltrazuril inhibite nuclear division & microchondril activity. Totrazuril damages the wall forming bodies of microgametes & causes severe vascuolisation by inflation of the endoplasmic reticulum in all intracellular development stages of Emeria spp. 2) Attact endogenous stages affected of Emeria speciesFor example Toltrazuril against developing first & second generation schizont & gametes of progenic Emeria spp.