ABSTRACT Halfa-bar (Cymbopogon proximus), is an aromatic grass widely growing in Upper Egypt. This herb is recommended for medical purposes as an effective diuretic, renal or abdominal antispasmodic agent. Objectives of this study: Evaluate the potential effects of Halfa-bar on the pregnant albino rats during the gestation period. Material and methods: The virgin female rats mated with male then the pregnant rats treated orally with Human Equivalent Dose (HED) of the proximol which equivalent 0.05 mg/ kg rat from 5th -18th Gestational Day (GD). At day 20 of pregnancy, all rats were anesthetized and killed to obtained maternal -fetal data (placenta). Results: The current study indicated that, there is statistically significant (P ≤ 0.05) reduction in the treated placental weight. Also, the light microscopic examination of the placental specimens using haematoxylin and eosin (H&E) staining revealed the presence of various vacuoles in the cytoplasm and nuclei of the giant cells. There is an increase in the number of apoptotic cells and irregular dilatation of maternal sinusoids in the labyrinth zone. Else, microscopic investigation showed a depletion of the glycogen content in the basal and labyrinth layers and a positive caspase-3 in the spongitrophoblast cells. In the treated group, reduction in level of catalase activity (CAT) and significant elevation (P ≤ 0.05) in the level of malondialdehyde (MDA) were recorded. Conclusion: The pathological effects in placenta may be due to the accumulation of proximal and transplacental passage.