The present study aimed to investigate the effect of 3,3'-diindolylmethane (DIM) on inflammatory markers, estrogen receptors (ER), progesterone receptors (PR), level of glycoprotein and the mast cell population in 7,12-dimethylbenz (a) anthracene (DMBA) 25mg/kg b.wt. inducedrat mammary carcinogenesis. After 8 weeks of tumor formation, rats had access to an oral administrated with DIM 10mg/kg b.wt. and DIM@CS-NP 0.5mg/kg body weight respectively for 8weeks. The oral administration of DIM@CS-NP 0.5mg/kg b.wt. suppressed the Cox-2, NF-κB and TNF-α protein expression on DMBA induced rats compared to DIM 10mg/kg b.wt. The ER/PR levels were increased on DMBA induced rats, treated with DIM@CS-NP 0.5mg/kg b.wt. reduced ER/PR level as well as glycoprotein and mast cell population than DIM 10mg/kg b.wt. The result shows that, DIM@CS-NP 0.5mg/kg b.wt. has the potentially inhibit abnormal levels of inflammatory markers, ER, PR, levels of glycoprotein and mast cell population compared to DIM 10mg/kg b.wt.