Amprolium is an antiprotozoal agent used for the prevention of coccidiosis in poultry. Amprolium has good activity against Eimeria tenella and E. acervulina in poultry and can be used as a therapeutic agent for these organisms. It only has marginal activity or weak activity against E. maxima, E. mivati, E. necatrix, or E. brunetti. It is often used in combination with other agents (e.g., ethopabate) to improve control against those organisms.