337HAEMATOLOGICAL STUDIES IN RESPONSE TO LONG TERM GENISTEIN ADMINISTRATION IN ALBINO MICE, Mus musculus.Soy isoflavone genistein is a phytoestrogen that mediates its functions via interaction with estrogen receptor β like endogenous estradiol 17-β. This research was conducted to determine the effects of prolonged oral genistein administration on mice, with specific interest on haematological changes. Approximately 6-8 weeks old thirty mature male and female albino mice, Mus musculus, weighing approximately 30 ± 5 g were assigned to two groups, where the first served as the vehicle treated control (receiving 1:4 DMSO:PBS only) and second as the experimental group and received 10 mg genistein/kg body weight/day (dissolved in 1:4 DMSO: PBS) for 30, 60 and 90 days. Post treatment blood samples were collected and used for haematological studies like total count of Red Blood Cells (RBC), White Blood Cells (WBC), Haemoglobin (Hb) content and differential count of WBC. Comparisons between control and treated animals (two way ANOVA analysis at p<0.05 to p<0.001) showed decreased RBC count, Hb content and neutrophil percentages, whereas WBC count, lymphocyte, eosinophil and monocyte percentages were increased after treatment. Together the results entail for no severe untoward effects on blood after prolonged daily genistein administration, unlike other exogenous estrogen analogues.arunimadattabanik@gmail.comResearch4122013Genistein,Mice,Haematology,EstrogenArunima Datta Banik,Shushovan Banik,Vinoy K ShrivastavaLaboratory of Endocrinology, Department of Bioscience, Barkatullah University, Bhopal-462026 (M. P.), India,Department of Zoology, Regional Institute of Education, NCERT, Bhopal (M. P.), India,Laboratory of Endocrinology, Department of Bioscience, Barkatullah University, Bhopal-462026 (M. P.), India