Aim and Background:.Cytochalasin B is presently being used as a cytokinesis inhibitor in the cell divisions to treat some types of cancer.

Materials and Methods:.Balb/c male mice (25-30 gr) are divided into 2 groups:control and experimental.The control group received distilled water whereas experimental groups were injected into abdominal cavity with cytochalasin B (1, 2, 3 and 5 mg/kg BW) . After 24 hours, sacrificed after being anesthetized by chloroform. Both femora were dissected, and bone marrow cells were flushed out with 1 ml Kcl and pipetted several times. The cell suspension was centrifuged at 1000 rpm for 5 min, the supernatant was withdrawn, and the cell pellet was resuspended and placed on a clean glass slide. Results: .This research seeks to determine the appropriate dosage of cytochalasin B to inhibit cytoplasm divisions. 1, 2, 3, and 5 mg/kg.bw of the medicine was used per kilogram of mice weight and the result was evaluated 24 hours after the treatment. The micronuclei assay was used to detect binuclei pronormoblast.Statistical analysis was performed with ANOVA and Tukey using SPSS software.

Conclusion:.In this study ,the results indicate the highest frequency of the binuclei pronormoblast (stopped in cytokinesis) when a 3mg/kg.bw dosage was taken for each kilogram of mice.