Eighty male albino rats of Westar strain (350 ± 10 g), 10 to 12 weeks old were divided into four groups. The groups treated are as following. The first control group (Gp. I) was given intraperitoneally in normal saline (1 mL). The second group (Gp. II) was orally infected with 3 × 10¹² CFU of E. coli /Kg. BW. The third group (Gp. III) was infected with E. coli and treated with (0.5%) lactoferrin (LF) 72 hours before E. coli infection in filtered tap water for the duration of the experiment (21 days). The fourth group (Gp. IV) was administrated with LF only (0.5%) in drinking water. Two separate blood samples were collected from heart puncture at the end of 1^st, and 3^rd week post-treatment for immunological studies. The Leukogram in E. coli treated group was insignificant compared with the control group while lymphocytosis was clear compared with the infected group. Total protein, albumin, α-globulin and β-globulin were insignificantly