Monosodium glutamate (MSG) is a sodium salt of glutamic acid that enhances the flavor of certain foods. It plays an important role in the pathogenesis of anovulatory infertility. This study was carried out to evaluate the histological, histochemical as well as immunohistochemical effects of MSG on the ovaries, uterus and vagina of adult female Wistar rats and the possible ameliorative role of carob (Ceratonia Siliqua). In the present work, twenty- four Wistar rats were divided into four groups (n=6): Control group received 0.5ml saline solution, carob-group, feeding on diet containing 5% carob powder, MSG- treated group received 400 mg/kg b.wt and ameliorative group received MSG 400mg/kg b.wt simultaneously with feeding on diet containing 5% carob powder. In MSG treated rats, the serum estrogen level was significantly decreased. The histopathological results showed ovarian atretic follicles, fragmented oocyte, vascular congestion, and vacuolated stroma. The uterus exhibited a comparative reduction in the endometrial thickness and loss of endometrial glands associated with cellular hyperplasia and reduced vacuolated cells. In MSG treated group, the vaginal epithelium appeared relatively thin, folded and hypertrophied with sign of cornification. Histochemically, a weak reaction for PAS stain was remarked in investigated sections of MSG- treated rats. On the other side, an intense positive reaction for silver stain was recorded in the ovarian stroma and peripheral layers of atretic follicles as well as spreading in endometrium of uterus and lumina sheath of vagina. Immunohistochemically, MSG-treated group exhibited intense positive reaction for CD31and CD68 and activated caspase3 compared to carob-ameliorated MSG and the control. The authors concluded that, feeding of MSG-treated group on diet containing 5% carob powder led to marked amelioration of histopathological lesions induced in ovaries, uterus and vagina by MSG attributed to the biological benefits of its phytochemical components.