In this study the adverse effect of Salmonela pullorum on body performance, immuno-biochemical and pathological alterations in balady chickens with treatment. A total of 100 cloacal swaps (50 from freshly dead chicks - 50 from chicks suffering from diarrhea) were collected from chickens in private locality in Sharkia Provence for isolation and identification of Salmonlla spp, from infected chickens. Nine positive swabs for sale (9) were 4 single isolates {(S. enteritidis (1),S. typhimurium (1), S. pullorum, (2)} and 5 mixed isolates {( S. enteritidis + S. typhimurium, (1), S. enteritidis + S. pullorum, (1), S. typhimurium+ S. pullorum, (2)}. isolated Sale were sensitive to doxycycline. A total of 120, one day old balady chickens (60 healthy and 60 experimantally infected with S. pullorum) were divided into 4 groups, 1^st group healthy chicks non infected non treated, 2^ndgroup treated with doxycycline, 3^rdgroup infected non treated and 4^th group chicks infected and treated with doxycycline. Specimens from internal organ were taken for pathological changes and estimation of doxycycline residues.
Healthy chickens received doxycycline treated and sal infected chicks non treated showed significant reduction in phagocytosis, killing %, total protein, albumin, A/G ratio and significant elevation in total, a, b globulins, AST, ALT, ALP, uric acid, creatinine beside non signifycant reduction in eosinophil, basophil, monocyte and non significant increase in g globulin. Healthy chickens received doxycycline showed significant decrease in heterophilis and significant increase in weight gain, lymphocyte beside non significant leukocytosis. Sal infected chicks showed clinical signs as ruffled feathers, emaciation, droppy wings, anorexia, diarrhea and dehydration, mortality rate was 20%. Significant reduction in body weight, lymphocyte and significant increase in leukocytosis and heterophilis. Salmmnellosis infected and treated chicks showed reduction in clinical signs, mortality rate  decreased to 3.33 % and reduction in Sal re-isolation post treatment was recorded beside improve in immunological and biochemical parameter at 7^th day post treatment. Doxycycline residues were detected in high levels in kidney followed by liver then breast muscle at 1^st and 4^th days post administration and completely disappeared from all tested tissues at 7^th days post administration. Doxcycline residue and histopathological changes were studies
 It could be concluded that Salmonellosis induce changes in biochemical parameters and doxycycline reduce severity of Salmonelosis and improvement of hepatorenal functions.