Blackhead disease (Histomonosis) in a dangerous parasite/ protozoan in poultries, especially chickens and turkeys. This disease is caused by anaerobic protozoan parasite which its science name is Histomonas meleagridis. Diseased poultries are depression, reduced appetite, Sulphur-yellow diarrhea, skin of head becomes pale or cyanotic, ceca and liver is swollen, caseous cores with white and liver appears gangrene sports as “Chrysanthemum”. Diseased chickens were died, if they are not treated immediately, the mortality may be 85%- 95%.