Technical Abstract: Exudative diathesis, a condition caused by a selenium (Se)/vitamin E deficiency, was studied in chicks. Trios of chicks that showed clinical signs of exudative diathesis were matched for severity. One was injected subcutaneously with 0.5 mL distilled water, and the other two received 15 ug of Se in 0.5 mL distilled water. A chick fed a diet with supplemental Se also received 0.5 mL distilled water. Blood was collected from three chicks 2 d after injection, and from the other chick, 6 d after injection. After blood was collected, pectoral muscle and bone marrow were collected. Deficient chicks showed varying degrees of necrosis in pectoral muscle, whereas recovering chicks had extensive fibrosis in pectoral muscle. An analysis of blood showed differences in carbon dioxide glucose, Se, glutathione peroxidase, alanine aminotransferase, aspartate aminotransferase, and creatine kinase. Heterophils and monocytes were increased in deficient chicks; lymphocytes, basophils, and hemoglobin decreased. After 6 d of recovery, all of the changes noted above were correcting toward normal. Eosinophils, in contrast, were unaffected by a deficiency, but increased in recovering chicks. It is hypothesized that cytokines associated with the inflammatory response accentuate the clinical signs of exudative diathesis.