Fats, a broad term for fats and oils, are sourced from either plants or animals. They function as energy storage and are crucial in various biological processes. This study aimed to examine the effects of tallow and olive oil on certain hematological and biochemical parameters in healthy albino rats. Twenty-eight male albino rats were divided into four groups, each containing seven animals. Groups given different treatments orally: Distilled water (control group), sheep tallow (Sh-T group), bovine tallow (B-T group), and olive oil (OO group). At the end of the third month, blood samples were collected from the fasting rats for hematological and biochemical analysis. Our results show that the oral administration of Sh-T, B-T, and OO did not cause significant changes in body weight (BW), food intake (FI) and level of serum of fibrinogen (FIB), albumin (ALB), C-reactive protein (CRP), or blood cell counts, including white blood cells (WBCs), red blood cells (RBCs), lymphocytes, neutrophils, platelets, and the erythrocyte sedimentation rate (ESR), when compared to the control group. However, total protein levels in the Sh-T and B-T groups, as well as globulin levels in the Sh-T and OO groups, showed significant increases, whereas the OO and B-T groups demonstrated a significant decrease in monocyte and eosinophil counts compared to the control group. It can be concluded that neither sheep nor bovine tallow nor olive oil negatively affects body weight or serum liver proteins, nor do they induce substantial hematological alterations
