The effect of the antibiotic cefoperazone was examined. The experiment was conducted on white male mice. The experiment was divided into three groups, 11-12 mice were allocated to each group to conduct different experiments, It was injected Intraperitoneal into the groups for 7 consecutive days. The control group was given distilled water throughout the experimental days. The second group was given the antibiotic cefoperazone at a dose of 500?mg/kg/day. The third group was given the antibiotic cefoperazone 800?mg/kg/day. Cefoperazone affects blood components, causing a noticeable increase in the total number of blood cells, a slight increase in the number of red blood cells, and an increase in hemoglobin and hematocrit. It also caused an increase, but it did not constitute a significant difference in blood counts. As for white blood cells, there was a significant difference for lymphocytes and eosinophils, and there was an increase in neutrophils, while for Basophil cells there was no significant increase.