This study was carried out to evaluate the effect of two medicinal plants: Echinacea Purpura and Star anise for treating and prevention of infectious bronchitis virus (IBV) in chickens via assessment of their immune stimulating effect in IBV challenged chicks. 160 one day old Cobb® unsexed broiler chicks with average body weight 46.3 g. Chicks were classified into 8 equal groups (20 of each). The 1st group served as a control negative, the 2nd group served as a control positive (infected with IBV virus at day 21, non- treated), the 3rd group received Echinacea from the 7th till 21st day and infected with IBV virus at day 21, the 4th group received Star anise from the 7th till 21st day and infected with IBV virus at day 21, the 5th group received both Echinacea and Star anise from the 7th till 21st day and infected with IBV virus at day 21, the 6th group infected with IBV virus at day 21, then received Echinacea from the 21st till 42nd, the 7th group infected with IBV virus at day 21then received star anise from the 21st till 42nd, and the 8thgroup infected with IBV virus at day 21, then received both Echinacea and Star anise from the 21st till 42nd. Estimation of the collected samples (blood and sera) were made at different periods (7th, 14th, 28th and 35th days) to determine the effects of the used drugs on some hematological, and biochemical parameters. In addition, tissue specimens from liver and trachea were taken for histopathological examination. The obtained results evoked a significant increase in WBCs, heterophiles, lymphocytes, monocytes and esinophils counts in the groups treated with Echinacea and star anise compared with that of the control group. Serum ALT, AST, serum urea and creatinine results revealed a significant increase in groups treated with Echinacea and star anise compared with the control group, while GSH, SOD and NO revealed decrease in groups treated with Echinacea and star anise compared with the control group.  It could be concluded that the use of Echinacea and star anise as antivirals is positively beneficial in prevention and treatment of infectious bronchitis virus in poultry. Moreover, the use of the combination of both plants when used together have  more powerful effects in the prevention and treatment of IBV in poultry.