This study was conducted on laying chick breed high line, 140 chicks one day old were divided into four groups: first control, second was given Peganum harmala in food, Third given vaccine and Peganum harmala. The fourth was given vaccine only. Bivalent vaccine Rispens, CVI988 and HVT was used at one day old by intramuscular injection. Sample of lymphatic organs, spleen, thymus, and Bursa of Fabricious were taken at days 3, 10, 16, 22, 28, 34, 42 for gross and histological study. Blood smears were taken at the same days for measuring stress factor and Phagocytic index. The gross reactions vary from congestion to enlargement of organs and hemorrhage after vaccination comparable with control. Paleness appear in those groups treated with Peganum harmala.Histological sections of spleen, thymus showed clear changes representing by hemorrhage, perivascular cuffing and depletion of lymphocytes in the germinal center of the most of lymphatic organs such as thymus, spleen, and Bursa of Fabricious, Phagocytic index showed significant increase in all groups vaccinated and unvaccinated groups compared to control group. Stress factor showed significant increase in all groups also.